Diagnostic

ABSTRACT

A method of diagnosing or monitoring Mycobacterium avium subspecies paratuberculosis (MAP) infection, which method comprises detecting the presence of the polypeptide (MAP P900) encoded by the positive strand of IS900, or a fragment thereof, in a sample from a subject, wherein MAP P900, or a fragment thereof, is detected using an antibody, or an antigen-binding fragment thereof, that binds to MAP P900.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 andclaims the benefit of PCT Application No. PCT/GB2018/050075 having aninternational filing date of 11 Jan. 2018, which designated the UnitedStates, which PCT application claimed the benefit of Great BritainPatent Application No. 1700487.0 filed 11 Jan. 2017, the disclosures ofeach of which are incorporated herein by reference in their entireties.

REFERENCE TO SEQUENCE LISTING

This application contains a Sequence Listing submitted as an electronictext file named “Sequence_Listing_N407615US_PXT_JCH.txt”, having a sizein bytes of 32000 bytes, and created on 8 Aug. 2019. The informationcontained in this electronic file is hereby incorporated by reference inits entirety pursuant to 37 CFR § 1.52(e)(5).

FIELD OF THE INVENTION

The present invention relates to the detection of Mycobacterium aviumsubspecies paratuberculosis (MAP). In particular the invention relatesto diagnosis, monitoring and treatment of MAP infection, and ofdisorders associated with such infection. The invention providesantibodies that bind specifically to MAP proteins and peptide fragmentsspecific to MAP and to uses of those antibodies and peptide fragments.

BACKGROUND TO THE INVENTION

Mycobacterium avium subspecies paratuberculosis (MAP) is a mycobacterialpathogen that is a member of the Mycobacterium avium complex (MAC).Unlike other environmental MAC, MAP has the specific ability to causechronic inflammation of the intestine of a range of histopathologicaltypes in many animals including primates.

MAP was first reported from Germany in 1895 as the cause of chronicinflammation of the intestine in a dairy cow. The condition came to becalled Johne's disease (JD). During the first half of the 20^(th)century JD principally affected Europe and North America but it hassince spread worldwide to become a global problem.

MAP infection in the absence of apparent clinical JD can persist inlivestock for years during which time they shed MAP into their milk andonto pastures. Run-off from pastures contaminates rivers and surfacewaters from which humans may be exposed in aerosols and domestic watersupplies. Human populations may also be exposed to residual viable MAPin milk from which its elimination by pasteurisation is not assured. Thepresence of residual live MAP has recently been confirmed in infantpowered milk (Botsaris et al. “Detection of viable Mycobacterium aviumsubspecies paratuberculosis in powdered infant formula by phage-PCR andconfirmed by culture” International Journal of Food Microbiology 2016;216: 91-94). MAP is now known to be able to infect and cause chronicinflammation of the intestine in many species including primates. Itsinvolvement in the causation of Crohn's disease (CD) in humans has longbeen suspected but despite increasing evidence, this major public healthuncertainty has never been resolved (Hermon-Taylor. “Mycobacterium aviumsubspecies paratuberculosis, Crohn's Disease and the Doomsday Scenario”Gut Pathogens 2009; 1:15).

MAP has not so far been seen in diseased tissues in Crohn's disease andat present there is no practically applicable clinical diagnostic testfor MAP infection in human medicine. In humans the lack of a practicallyapplicable clinical diagnostic is a major unmet medical need (Nacy andBuckey, “Mycobacterium avium paratuberculosis: Infrequent Human Pathogenor Public Health Threat? A Report from the American Academy ofMicrobiology” 2008). Furthermore the MAP diagnostics available foranimals are not good at the early detection of low grade subclinicalinfection.

SUMMARY OF THE INVENTION

The present inventor has developed a sensitive and reliable method fordetecting Mycobacterium avium subspecies paratuberculosis (MAP). Theinventor has developed antibodies that are highly specific to MAP andthat recognise regions of MAP that are exposed on the surface of MAP andwithin and on the surface of MAP infected host cells. The antibodiesbind to the polypeptide encoded by the positive strand of MAP IS900.Using the antibodies, the inventor has shown that MAP is widely presentin samples from patients with Crohn's disease but also other diseasesand conditions including Psoriasis, Hashimoto's Thyroiditis, IrritableBowel Syndrome and others (Scanu et al. “Mycobacterium avium Subspeciesparatuberculosis Infection in Cases of Irritable Bowel Syndrome andComparison with Crohn's Disease and Johne's disease: Common Neural andImmune Pathogenicities” Journal Clinical Microbiology. 2007; 45:3883-3890). The inventor has detected MAP, not only in tissue samplesfrom the affected regions, but also in bodily fluids including blood andbreast milk. The inventor has shown that the antibodies may be used todetect MAP organisms, cells infected with MAP and cleaved MAPpolypeptide fragments.

Furthermore, the inventor has developed antibodies that are specificeither for a non-phosphorylated sequence within the polypeptide encodedby the positive strand of MAP IS900 or for the same sequences afterphosphorylation, i.e. the antibodies are mutually exclusive. Using thesenon-phosphorylation and phosphorylation specific antibodies, theinventor has found that the phosphorylation status may be used todetermine the status of the MAP infection. He has also found thatnon-phosphorylation and phosphorylation specific antibodies may be usedin combination to characterise the level and activity of the MAPinfection.

The inventor has identified peptide fragments of the MAP P900polypeptide that have maximum specificity for MAP and that areimmunogenic. The selection of the target amino acid sequences fromwithin the accessible extracellular amino terminal and carboxy terminalportions of the MAP P900 polypeptide is principally governed by theirspecificity for the MAP pathogen so that the diagnostic antibodies tothem do not cross react with closely related sequences.

Accordingly, the present invention provides a method of diagnosing ormonitoring Mycobacterium avium subspecies paratuberculosis (MAP)infection, which method comprises detecting the presence of thepolypeptide (MAP P900) encoded by the positive strand of IS900 (MAPIS900), or a fragment thereof, in a sample from a subject, wherein MAPP900, or a fragment thereof, is detected using an antibody, or anantigen-binding fragment thereof, that binds to MAP P900.

The antibody, or antigen-binding fragment thereof, preferably binds theregion of MAP P900 defined by amino acids 24 to 71 or 329 to 386 of SEQID NO: 1. Preferred antibodies, or antigen-binding fragments thereof,binds the region of MAP P900 defined by:

-   -   amino acids 26 to 71 of SEQ ID NO: 1;    -   amino acids or 329 to 385 of SEQ ID NO: 1;    -   amino acids 26 to 39 of SEQ ID NO: 1;    -   amino acids or 52 to 68 of SEQ ID NO: 1;    -   amino acids or 345 to 359 or 350 to 359 of SEQ ID NO: 1;    -   amino acids 26 to 71 of SEQ ID NO: 1, wherein serine 37 is        phosphorylated;    -   amino acids or 345 to 359 or 350 to 359 of SEQ ID NO: 1, wherein        serine 357 is phosphorylated and/or serine 358 is        phosphorylated.

The method of the invention may utilise two or more of said antibodies,or antigen-binding fragments thereof, to detect MAP P900. For example,the method may utilise:

-   -   at least one antibody that binds to the region of MAP P900        defined by amino acids 26 to 71 of SEQ ID NO: 1 and at least one        further antibody that binds to the region of MAP P900 defined by        amino acids or 329 to 385 of SEQ ID NO: 1;    -   at least one antibody that binds to the region of MAP P900        defined by amino acids 26 to 39 of SEQ ID NO: 1 and at least one        further antibody that binds to the region of MAP P900 defined by        amino acids or 52 to 68 of SEQ ID NO: 1;    -   at least one antibody that binds to the region of MAP P900        defined by amino acids 52 to 68 of SEQ ID NO: 1 and at least one        further antibody that binds to the region of MAP P900 defined by        amino acids or 345 to 359 or 350 to 359 of SEQ ID NO: 1;    -   at least one antibody that binds to the region of MAP P900        defined by amino acids 26 to 71 of SEQ ID NO: 1, wherein serine        37 is optionally phosphorylated and at least one further        antibody that binds to the region of MAP P900 defined by amino        acids or 345 to 359 or 350 to 359 of SEQ ID NO: 1, wherein        serine 357 and/or serine 358 is optionally phosphorylated.

In one embodiment, the method of the invention comprises determiningwhether the region of MAP P900 between amino acids 273 to 406 of SEQ IDNO: 1, or a fragment of either thereof, has been cleaved frommembrane-bound MAP P900 and optionally whether the cleaved region of MAPP900, or fragment thereof, has spread from microbial cells and/or hostcells containing membrane bound MAP P900.

In one embodiment, the method of the invention uses at least oneantibody that specifically binds to a non-phosphorylated MAP P900sequence and at least one further antibody that specifically binds tophosphorylated MAP P900 sequence. Preferably, the non-phosphorylated MAPP900 sequence is MVINDDAQRLLSQR (SEQ ID NO:2), and the phosphorylatedMAP P900 sequence is MVINDDAQRLL[pS]QR (SEQ ID NO:3), or thenon-phosphorylated MAP P900 sequence is YLSALVSIRTDPSSR (SEQ ID NO:4) orVSIRTDPSSR (SEQ ID NO:5), and the phosphorylated MAP P900 sequence isYLSALVSIRTDPS[pS]R (SEQ ID NO:6), YLSALVSIRTDP[pS]SR (SEQ ID NO:7),YLSALVSIRTDP[pS][pS]R (SEQ ID NO:13), VSIRTDPS[pS]R (SEQ ID NO:98),VSIRTDP[pS]SR (SEQ ID NO:9) or VSIRTDP[pS][pS]R (SEQ ID NO:8).

The sample is preferably a sample of a body fluid or a tissue sample.The body fluid may be, for example, blood, semen, amniotic fluid,cerebrospinal fluid, synovial fluid or breast milk, or the tissue maybe, for example, skin, muscle, gastrointestinal tract, thyroid, lymphnode, brain or genitourinary tract.

The subject preferably has Crohn's disease, psoriasis, thyroiditis,Parkinson's disease, type 1 diabetes, arthritis, ankylosing spondylitis,irritable bowel syndrome, ulcerative colitis, inflammatory boweldisease, Alzheimer's disease, multiple sclerosis, sarcoidosis,idiopathic pulmonary fibrosis and/or chronic fatigue syndrome.

The invention also provides:

-   -   An antibody, or antigen-binding fragment thereof, which        specifically binds to the region of MAP P900 defined by amino        acids 26 to 71 of SEQ ID NO: 1, preferably an antibody, or        antigen-binding fragment thereof, that binds to the amino acid        sequence MVINDDAQRLLSQR (SEQ ID NO:2), AAVTTLADGGEVTWAID (SEQ ID        NO: 10) or MVINDDAQRLL[pS]QR (SEQ ID NO: 3);    -   An antibody, or antigen-binding fragment thereof, which        specifically binds to a phosphorylated sequence within the        region of MAP P900 defined by amino acids 26 to 71 or 345 to 371        of SEQ ID NO: 1; preferably an antibody, or antigen-binding        fragment thereof, that binds to the sequence MVINDDAQRLLSQR (SEQ        ID NO:2) or YLSALVSIRTDPSSR (SEQ ID NO:4), when one or more of        the serine residues is phosphorylated;    -   An antibody, or antigen-binding fragment thereof, that        specifically binds to the amino acid sequence YLSALVSIRTDPSSR        (SEQ ID NO:4) or NLKRPRRYDRRLLRA (SEQ ID NO:11) or a        phosphorylated form of either thereof, within the region of MAP        P900 defined by amino acids 329 to 360 of SEQ ID NO: 1;    -   Use of an antibody, or antigen-binding fragment thereof, as        defined herein in an ex vivo method of diagnosing or monitoring        MAP infection;    -   Use of an antibody, or antigen-binding fragment thereof, as        defined herein in an ex vivo method of monitoring treatment of        MAP infection, or treatment of a subject having Crohn's disease,        Ulcerative Colitis, Psoriasis, Thyroiditis, Sarcoidosis,        Parkinson's disease, Multiple Sclerosis, Type 1 Diabetes,        arthritis, ankylosing spondylitis and irritable bowel syndrome,        inflammatory bowel disease, Alzheimer's disease, multiple        sclerosis, idiopathic pulmonary fibrosis and/or chronic fatigue        syndrome;    -   Use of an antibody, or antigen-binding fragment thereof, as        defined herein to detect MAP in a food product, such as milk,        another diary product or a meat product;    -   Use of an antibody, or antigen-binding fragment thereof as        defined herein in a method for detecting MAP in an environmental        sample, such as a sample of surface water, river water,        water-treatment plant water, domestic water, or an aerosol, soil        or sediment;    -   Use of an antibody, or antigen-binding fragment thereof, as        defined herein to capture a peptide for Mass Spectrometry (MS)        or Mass Cytometry characterisation;    -   A peptide fragment of MAP P900 of up to 40 amino acids        comprising one or more of the following sequences:        MVINDDAQRLLSQR (SEQ ID NO:2), VTTLADGGEVTWAID (SEQ ID NO:12),        NLKRPRRYDRRLLRA (SEQ ID NO:11), VSIRTDPSSR (SEQ ID NO:5) and        YLSALVSIRTDPSSR (SEQ ID NO:4), wherein the peptide is optionally        phosphorylated, wherein the phosphorylated peptide preferably        comprises one of the following sequences: MVINDDAQRLL[pS]QR (SEQ        ID NO: 3) or YLSALVSIRTDPS[pS]R (SEQ ID NO:6),        YLSALVSIRTDP[pS]SR (SEQ ID NO:7) or YLSALVSIRTDP[pS][pS]R (SEQ        ID NO:13);    -   A method of generating an antibody that specifically binds to        MAP P900, which method comprises administering a peptide as        defined herein to a laboratory animal to generate an immune        response and isolating antibodies from the animal;    -   An antibody, or antigen-binding fragment thereof, as defined        herein for use in therapeutic or diagnostic method carried out        on the human or animal body    -   An antibody, or antigen-binding fragment thereof, as defined        herein for use in a method of treating or preventing MAP        infection.

BRIEF DESCRIPTION OF THE SEQUENCE LISTING

FIG. 1 shows the staining of MAP ISP900 in the ileum in a 40 year oldman with Crohn's disease using two specific monoclonal antibodiesagainst Mycobacterium avium subspecies paratuberculosis (MAP). These areA1 in red (top right) and A4 in green (top left). The bottom panel showsthe two together.

FIG. 2 shows the transverse colon of an individual with Crohn's diseasestained using the A1 (red/top right) and A4 antibodies (green/top left).The bottom panel shows the two together.

FIG. 3 shows the ileum of an individual with Crohn's disease stainedusing the A1 (red/top right) and A4 antibodies (green/top left). Thebottom panel shows the two together.

FIG. 4 shows the rectum of a 3 month old male child with Crohn's diseasestained using the A1 (red/top right) and A4 antibodies (green/top left).The bottom panel shows the two together.

FIG. 5 shows a gut arteriole in a sheep with Johne's disease stainedusing the A1 (red/top right) and A4 antibodies (green/top left). Thebottom panel shows the two together.

FIG. 6 shows a gut arteriole in a an individual with Crohn's diseasestained using the A1 (red/top right) and A4 antibodies (green/top left).The bottom panel shows the two together.

FIG. 7 shows MAP-laden white blood cells in breast milk stained usingthe A0X antibody.

FIG. 8 shows MAP-Laden white blood cells in blood. A phase contrastimage of the cells is shown (top right) and staining with the A0Xantibody (top left). The bottom panel is an overlay of the two images.

FIG. 9 shows a monocyte cell from the blood of a 25 year old man withsevere Crohn's disease stained A4 in red (top right) and XA4P in green(top left). The cell is not perforated so staining is directed to thesurface of the cell and almost certainly perturbs its function. Thetargets of the monoclonal antibodies contain the same amino acidsequence which includes 1 serine residue. This serine is notphosphorylated in the A4 target and is phosphorylated in the XA4Ptarget. The phosphorylation event causes the targets to change theirimmunogenicity so that although they both crowd the cell surface inclose apposition with one another they do not ad-mix. The use of A4 andXA4P monoclonal antibodies therefore allows the actions of the 2 MAPproducts to be used to trace the molecules and study their locations.

BRIEF DESCRIPTION OF THE SEQUENCE LISTING

SEQ ID NO: 1 is the amino acid sequence of P900 encoded by the positivestrand of MAP IS900 in MAP.

  1 MTVTEVVVAQPVWAGVDAGKADHYCMVINDDAQRLLSQRVANDEAALLELIAAVTTLADG  61GEVTWAIDLNAGGAALLTALLIAAGQRLLYIPGRTVHHAAGSYRGEGKTDAKDAAIIADQ 121ARMRHDLQPLRAGDDIAVELRILTSRRSDLVADRTRAINRMRAQLLEYFPALERAFDYNK 181SRAALILLTGYQTPDALRSAGGARVAAFLRKRKARNADTVAATALQAANAQHSIVPGQQL 241AATVVARLAKEVMALDTEIGDTDAMIEERFRRHRHAEIILSMPGFGVILGAEFLAATGGD 301MAAFASADRLAGVAGLAPVPRDSGRISGNLKRPRRYDRRLLRACYLSALVSIRTDPSSRT 361YYDRKRTEGKRHTQAVLALARRRLNVLWAMLRDHAVYHPATTTAAA Underline denotespredicted transmembrane regions

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a novel method for detectingMycobacterium avium subspecies paratuberculosis using antibodies thatspecifically bind to the polypeptide encoded by the positive strand ofIS900 (P900). The amino acid sequence of MAP P900 is shown in SEQ ID NO:1.

The present invention relates to a method of detecting the presence orabsence of Mycobacterium avium subspecies paratuberculosis (MAP) in asample, which method comprises detecting the presence or absence of thepolypeptide (P900) encoded by the positive strand of IS900 (MAP IS900),or a fragment thereof, in a sample from a patient, wherein the MAP P900polypeptide, or a fragment thereof, is detected using an antibody, or anantigen-binding fragment thereof, that binds to P900.

In particular, the present invention relates to a method of diagnosingor monitoring Mycobacterium avium subspecies paratuberculosis (MAP)infection, which method comprises detecting the presence of thepolypeptide encoded by the positive strand of IS900 (MAP 1S900), or afragment thereof, in a sample from a patient, wherein the MAP P900polypeptide, or a fragment thereof, is detected using an antibody, or anantigen-binding fragment thereof, that binds to MAP P900.

Antibody

The present application utilises antibodies, or antibody-bindingfragments thereof, that specifically bind to the polypeptide encoded bythe positive strand of IS900 (P900) and/or to a fragment thereof. Theamino acid sequence of P900 is shown in SEQ ID NO: 1. More preferably,the antibodies, or antibody-binding fragments thereof, bind to a regionof P900 extracellular to MAP. The region extracellular to MAP ispreferably within amino acids 24 to 71, preferably within amino acids 26to 71, of SEQ ID NO: 1 (N-terminal extracellular region) or within aminoacids 329 to 386, preferably within amino acids 329 to 385, of SEQ IDNO: 1 (C-terminal extracellular region).

The present invention provides antibodies and antibody binding fragmentsthereof that specifically bind to the N-terminal extracellular region orthe C-terminal extracellular region of MAP P900.

Preferred antibodies, or antigen-binding fragments thereof, of theinvention include antibodies and antibody fragments which specificallybind to the region of P900 defined by amino acids 26 to 71 of SEQ ID NO:1 or which specifically bind to a phosphorylated sequence within theregion of P900 defined by amino acids 26 to 71 or 329 to 385 of SEQ IDNO: 1.

The antibodies, or antibody-binding fragments thereof, bind to aminoacid sequences within P900 that are specific for MAP, i.e. theantibodies, or antibody-binding fragments thereof, bind to a unique MAPsequence. In particular, the sequences to which the antibodies bind arenot found in homologous sequences encoded by DNA insertion elements inclosely related M. avium sp. known in the art, in particular in M aviumspp avium, M avium ssp sylvat, M avium 2333, M avium chebnae, Mporcinum, M Rhodesiac, M thermoresistibile, M avium 16 p44, M avium2285; M intracellulare; M xenopi, M avium p44, M avium silvaticum, Mavium hominissuis, Liefsonia xyli TR and/or M avium AF071067. Theantibodies, or antibody-binding fragments thereof, bind to a MAP P900sequence but do not bind to homologous sequences from other relatedorganisms.

The antibodies, or antibody-binding fragments thereof, may bind to alinear epitope (i.e. to a particular amino acid sequence) within P900.The antibodies, or antibody-binding fragments thereof, are typicallygenerated using a synthetic peptide fragment of P900 as an immunogen.Therefore, the antibodies or antibody fragments, may bind to a peptidefragment of P900. Antibodies that bind to a fragment of P900 as well asto full length P900 may be used in a method of the invention, as mayantibodies which bind only to a fragment of P900, particularly where afragment to which the antibody binds is cleaved from full length P900 incells infected with MAP which are then progressively depleted of thatfragment which may be transferred to another cell. It is preferred thatthe antibody binds to P900 on the surface of mycobacterial (MAP) cellsand host cells infected with MAP. Such antibodies typically also bind toa peptide fragment of MAP.

The antibody, or antigen-binding fragment thereof, may be one that bindsspecifically to a non-phosphorylated sequence within P900, or one thatbinds specifically to a phosphorylated sequence within P900. Theantibody, or antigen-binding fragment thereof, may be one that binds toan amino acid sequence of P900 regardless of the phosphorylation statusof P900.

The P900 polypeptide may be phosphorylated at serine, tyrosine and/orthreonine residues. The antibody, or antigen binding fragment thereof,may bind specifically to a P900 sequence that is phosphorylated at oneor more of these residues. Preferably the phosphorylated residue is aserine residue. The antibody, or antigen binding fragment thereof, maybind only to a P900 sequence in which one or more serine residue (and/orone or more tyrosine and/or one or more threonine residue) isphosphorylated or only to the P900 sequence in which one or more serineresidue including adjacent serine residues (and/or one or more tyrosineand/or one or more threonine residue) is not phosphorylated.

The antibody, or antigen-binding fragment thereof, may bind specificallyto a non-phosphorylated sequence within amino acids 24 to 71 or 329 to386 of SEQ ID NO: 1, such as within amino acids 345 to 371 of SEQ IDNO: 1. The antibody, or antigen-binding fragment thereof, mayspecifically bind to a phosphorylated sequence within the region of P900defined by amino acids 24 to 71 or 329 to 386 of SEQ ID NO: 1,preferably within amino acids 26 to 71 or 345 to 371 of SEQ ID NO: 1.

The antibody, or antigen-binding fragment thereof, may specifically bindto an amino acid sequence within:

-   -   residues 24 to 44 of SEQ ID NO: 1 (YCMVINDDAQRLLSQRVANDE (SEQ ID        NO: 14)—designated the A0X site), preferably residues 26 to 39        of SEQ ID NO: 1 (MVINDDAQRLLSQR (SEQ ID NO:2)—designated A0X) or        residues 26 to 39 in which S37 is phosphorylated        (MVINDDAQRLL[pS]QR (SEQ ID NO: 3)—designated A0XP);    -   residues 52 to 71 of SEQ ID NO: 1 (AAVTTLADGGEVTWAIDLNA (SEQ ID        NO:15)—designated the XA1 site), preferably residues 52 to 68 of        SEQ ID NO: 1 (AAVTTLADGGEVTWAID (SEQ ID NO: 10)—designated XA1);        or    -   residues 329-360 of SEQ ID NO: 1        (NLKRPRRYDRRLLRACYLSALVSIRTDPSSRT (SEQ ID NO: 16)), preferably        residues 329 to 343 of SEQ ID NO: 1 (NLKRPRRYDRRLLRA (SEQ ID        NO:11)—designated A3), residues 345 to 359 of SEQ ID NO: 1        (YLSALVSIRTDPSSR (SEQ ID NO:4)—designated XA4), residues 345 to        359 of SEQ ID NO: 1 in which one or more of the serine residues        is phosphorylated, preferably in which either S357        (YLSALVSIRTDP[pS]SR (SEQ ID NO:7)) or S358 (YLSALVSIRTDPS[pS]R        (SEQ ID NO:6)—designated XA4P) is phosphorylated or both S357        and S358 are phosphorylated (YLSALVSIRTDP[pS][pS]R (SEQ ID        NO:13));    -   residues 350 to 359 of SEQ ID NO: 1 (VSIRTDPSSR (SEQ ID        NO:5)—A4), or residues 350 to 359 of SEQ ID NO: 1 in which        either S357 or S358 is phosphorylated or both S357 and S358 are        phosphorylated;    -   residues 370-386 of SEQ ID NO: 1 (KRHTQAVLALARRRLNV (SEQ ID        NO:17)); or    -   residues 370-385 of SEQ ID NO: 1 (KRHTQAVLALARRRLN (SEQ ID NO:        18)).

The antibody may be a monoclonal or polyclonal antibody, preferably amonoclonal antibody, or antigen-binding fragment thereof. The antibodymay be a human, humanised or chimeric antibody, or may be a mouseantibody or antibody from another species such as Rabbit, Goat, Donkeyor Alpaca. The antibody may be a recombinant antibody.

The term “antigen-binding fragment” of an antibody refers to one or morefragments of an antibody that retain the ability to specifically bind toMAP P900 and/or a peptide fragment of MAP P900. Examples of suitablefragments include a Fab fragment, a F(ab′)₂ fragment, a Fab′ fragment, aFd fragment, a Fv fragment, a dAb fragment and an isolatedcomplementarity determining region (CDR). Single chain antibodies suchas scFv and heavy chain antibodies such as VHH and camel antibodies arealso intended to be encompassed within the term “antigen-bindingportion” of an antibody. The antigen-binding fragment may, for example,be: a single domain ‘Nanobody’ (Fridy et al. “A robust pipeline forrapid production of versatile nanobody repertoires.” Nature Methods.2014; 11: 1253-1260); a pegylated fragment; a bispecific fragment (e.g.two scFv fragments joined by a peptide linker); conjugated to abacterial toxin, or a mutated form thereof, such as Pseudomonas exotoxinA or Staphylococcal enterotoxin A; conjugated to polyethylene glycol; atandem diabody; or a dual affinity re-targeting (DART) molecule(Sheridan “Ablynx's nanobody fragments go places anotibodies cannot”Nature Biotechnology 2017 35: 1115-1117).

The antibody, or antigen-binding fragment thereof, may be labelled. Thelabel aids in the detection of the antibody bound to P900 in thedetection methods of the invention. The label may be a fluorophore, anenzyme such as Horse Radish Peroxidase, gold beads, a radioisotope, or atag such as a particular synthetic peptide epitope or a syntheticoligonucleotide or a lanthanide. Any suitable fluorophore may be used tolabel the antibody, or antigen-binding fragment. For example, thefluorophore may be green fluorescent protein, rhodamine, Oregon green,eosin or Texas red. Where the method of the invention uses a pair ofantibodies, or antigen-binding fragments thereof, each member of thepair is preferably labelled differentially, for example with differentlycoloured fluorophores, such as a red fluorophore and a greenfluorophore, so that binding of each of the antibodies to the sample maybe distinguished and/or so that co-localisation of the antibodies may bedetected.

Diagnosing and Monitoring MAP Infection

The invention provides the use of an antibody, or antigen-bindingfragment thereof, according to the invention in an ex vivo method ofdiagnosing or monitoring MAP infection. The method may further comprisetreating a subject diagnosed as having a MAP infection. The method mayfurther comprises altering the treatment of a subject having a MAPinfection, wherein the MAP infection is being monitored in the subject.For example, the treatment may be a treatment in which one or moreantimicrobial agent, such as a combination including Rifabutin andClarithromycin, is administered to the patient, either alone or incombination with one or more additional therapeutic agents. Thetreatment may be a prophylactic or therapeutic MAP vaccine. Thetreatment may comprise passive immunotherapy administering to thesubject anti-MAP monoclonal antibodies such as the antibodies describedherein.

The method of detecting MAP P900 provided by the invention may be usedto detect MAP infection in a subject. Typically the method is carriedout ex vivo using a sample taken from a human or animal subject. Thesubject may have, or be suspected of having, Crohn's disease, psoriasis,thyroiditis, Parkinson's disease, Multiple Sclerosis, type 1 diabetes,arthritis, ankylosing spondylitis, colitis, inflammatory bowel diseaseor irritable bowel syndrome, Alzheimer's disease, sarcoidosis,idiopathic pulmonary fibrosis and/or chronic fatigue syndrome. Thesubject may be a healthy subject. A healthy subject is a human or animalhaving no symptoms of a disease associated with MAP infection, such asany of the diseases listed above. In animals the subject may besuspected of being infected with MAP or of having Johne's disease. Theanimal may be any animal, but is preferably a laboratory animal, a wildanimal, a pet or is more preferably a farm animal. The farm animal ispreferably an animal used for milk production or for meat, such as acow, goat, sheep or deer. The method may be used to diagnose MAPinfection or to monitor MAP infection. MAP infection may be monitored todetermine the progress of the infection. Accordingly, the method of theinvention may be used to study the course of MAP infection and/or todetermine the status of the infection in a subject.

The antibodies, or antibody binding fragments thereof, specific for MAPP900 may be used singly, or in multiples, to diagnose, quantify andcharacterise MAP infections in humans and animals. For example, one,two, three, four, five or more antibodies may be used in a method of theinvention. Typically the antibodies used in a method of the inventionwill be specific for different P900 sequences and/or for the same P900sequences but in phosphorylated and non-phosphorylated forms.

The present inventor has found that infection with MAP, and/or cells ina subject infected with MAP, can be detected using antibodies specificfor MAP P900 to stain tissue samples taken from a subject. The stainingcan be viewed by any suitable means. Microscopy, in particular confocalmicroscopy, can be used to identify cells of a subject infected withMAP. MAP can be seen as distinct subcellular particles within infectedcells. The antibodies specific for MAP P900 may also be used to detectMAP P900 on the surface of the infected cells of a subject.

Furthermore, the method of the invention may comprise determiningwhether the region of MAP P900 between amino acids 26 to 71 and/or 273to 406 of SEQ ID NO: 1, or a fragment of either thereof, has beencleaved from membrane-bound MAP P900.

One way to do this is to use at least one antibody that specificallybinds to a first region of P900, such as the region between amino acids26 to 71 of SEQ ID NO: 1, and at least one antibody to a second regionof P900, such as the region between amino acids 273 to 406 of SEQ IDNO: 1. A fragment of P900 has been cleaved and released where theantibody to the first region of P900 does not co-localise with theantibody to the second region of P900. In this situation, there may besome partial co-localisation of the two antibodies, depending on thedegree of cleavage and release. Co-localisation of antibodies may bedetermined by any suitable method. For example, a first antibody may belabelled with a green fluorophore and a second antibody with a redfluorophore. Binding of the labelled antibodies to the sample may bevisualised using a suitable microscope (such as a confocal microscope).Observation of green or red staining indicates areas where just one ofthe first and second antibodies is bound, whereas gold, orange or yellowstaining shows where both antibodies are co-localised.

The fragment cleaved from P900 may be within the region 329 to 386, 329to 385, or 370 to 386 of SEQ ID NO: 1. Typically the fragment may bedetected using an antibody, or antigen-binding fragment thereof thatbinds to amino acids 329-360 of SEQ ID NO: 1, preferably residues 329 to359, 329 to 343, 345 to 360, 345 to 359, 350 to 359 or 350 to 360 of SEQID NO: 1, residues 329 to 360, 329 to 359, 345 to 360 or 345 to 359, 350to 359 or 350 to 360 of SEQ ID NO: 1 in which either S357 or S358 isphosphorylated or both S357 and S358 are phosphorylated.

The cleaved fragment detected by a method of the invention may bedetected in cells of the subject that are not infected with MAP cells,but that are adjacent to or close to infected host cells. In such cells,the antibodies stain the cytoplasmic compartment. The presence of a MAPP900 fragment in the cytoplasmic compartment of cells of the subject maybe used as an indicator of the stage of MAP infection.

The sample tested in a method of the invention may a sample of a tissue.The tissue is typically taken from the site of suspected infection. Thetissue sample may be a sample of skin, a sample from the mouth,gastrointestinal tract, thyroid, lung, lymph node, brain orgenitourinary tract. The sample may be a gut biopsy, particularly wherethe subject has Crohn's disease or is suspected of having Crohn'sdisease or another gastrointestinal disorder such as colitis,inflammatory bowel disease or irritable bowel syndrome. The gut samplemay be taken from any one or more of the oesophagus, stomach, duodenum,jejunum, ileum, cecum, appendix, colon and rectum and the perianalregion. The method of the invention may also be used to monitorvasculitis, by monitoring MAP infection in the blood vessels, forexample in the blood vessels of the gut. The sample may be skin wherethe subject has or is suspected of having Psoriasis. The sample istypically a thyroid sample where the subject has or is suspected ofhaving Hashimoto's thyroiditis.

MAP P900 and/or fragments thereof may also be detected in the blood andin other bodily fluids, such as breast milk or synovial fluid, from asubject infected with MAP. The sample tested in a method of theinvention may therefore be a sample of a bodily fluid such as blood,urine, semen, amniotic fluid, cerebrospinal fluid, synovial fluid, andsputum or breast milk.

The status of the MAP infection may also be determined using antibodiesspecific for non-phosphorylated P900 and antibodies that are specificfor phosphorylated P900. Typically the method uses antibodies that bindto the same amino acid sequence of P900, wherein a first antibody bindsto the non-phosphorylated sequence and the second antibody binds to thephosphorylated sequence.

For example, antibodies that bind to MVINDDAQRLLSQR (SEQ ID NO:2) can beused to detect the presence of P900 in gut tissues, whereas antibodiesthat bind to MVINDDAQRLL[pS]QR (SEQ ID NO: 3) do not stain gut tissuesin humans. However, antibodies to MVINDDAQRLL[pS]QR (SEQ ID NO: 3) dobind to P900 or a fragment thereof in infected white cells in humanblood (WBC) so that the presence of MVINDDAQRLL[pS]QR (SEQ ID NO: 3) inblood may indicate the progression of the MAP infection from gut toblood in the subject.

Antibodies to phosphorylated and non-phosphorylated forms of the same orsimilar P900 sequence, preferably MVINDDAQRLLSQR (SEQ ID NO:2) (A0X) andMVINDDAQRLL[pS]QR (SEQ ID NO: 3) (A0XP) or VSIRTDPSSR (SEQ ID NO:5) (A4)and YLSALVSIRTDPS[pS]R (SEQ ID NO:6) (XA4P), may be used to provide ameasure of the level of MAP infection. In this situation thenon-phosphorylated form of the sequence is the substrate and thephosphorylated sequence is the product of the activity of thephosphorylating enzyme. The substrate and the product are in a dynamicrelationship with each other where depletion of substrate is matched byincrease in product. At a given point in time, the sum total ofcirculating white blood cells (WBCs) and their individual lineagescontaining either the substrate, the product or both the substrate andthe product provides a measure of the proportion of circulating WBCsinfected with MAP. The ratio between the non-phosphorylated andphosphorylated peptides reflects the activity of the system likely toprovide clinical correlates of disease activity and responses totreatments. Typically where the antibodies are mutually exclusive, e.g.bind to either the phosphorylated sequence or to the non-phosphorylatedsequence but not to both, the total amount of antibody binding gives anindication of the total amount of P900 present in the sample and theproportion of host cells infected with MAP. For example, the numberand/or proportion of infected WBCs may be determined using the A0X andA0XP antibodies to detect MAP in WBCs. The number and/or proportion ofinfected WBCs correlates with the severity of infection. The severity ofinfection also correlates with inflammatory symptoms in the infectedindividuals, for example in people with Crohn's disease. In individualswith Crohn's disease, the percentage of infected WBCs in the blood hasbeen shown to be as high as about 50%, but may be lower as shown inTable 2.

The present inventor has demonstrated that the C-terminus of MAP P900 iscleaved by showing that A0X and/or A0XP antibody staining of theN-terminus does not always co-localise with XA4 and/or XA4P staining ofthe C-terminus. The antibodies and antibodies of the present inventionmay therefore be used to monitor the pathogenic mechanism involving thecleavage, release and/or trafficking of the C-terminus of MAP P900. Themethod of the invention may be used to monitor MAP infection followingtreatment of a subject. The treatment of the subject may be a treatmentintended to target the MAP infection, or a treatment of a disease thatis associated with or caused by MAP infection, such as Crohn's disease,Psoriasis, Thyroiditis, Parkinson's disease, Multiple Sclerosis,Alzheimer's disease, type 1 Diabetes, Arthritis, Ankylosing Spondylitis,Colitis, Inflammatory Bowel Disease or Irritable Bowel Syndrome,Sarcoidosis, idiopathic pulmonary fibrosis and/or chronic fatiguesyndrome. Thus, the invention provides a method for monitoring theeffectiveness of a treatment of MAP infection, or the effect of atreatment for any of the above conditions, or other condition, on MAPinfection. For example, the treatment may be a treatment in which one ormore antimicrobial agent, such as a combination including Rifabutin andClarithromycin, is administered to the patient, either alone or incombination with one or more additional therapeutic agents. Thetreatment may be a prophylactic or therapeutic MAP vaccine. Thetreatment may comprise passive immunotherapy administering to thesubject anti-MAP monoclonal antibodies such as the antibodies andpeptides described herein.

Uses of the Invention

The method of the invention may be used to detect MAP contamination ofclinical, environmental and/or food samples. In such methods, theantibodies, or antibody binding fragments thereof, specific for MAP P900may be used singly, or in multiples. For example, one, two, three, four,five or more antibodies may be used in a method of the invention.Typically the antibodies used in a method of the invention will bespecific for different P900 sequences or for the same P900 sequences butin phosphorylated and non-phosphorylated forms.

The invention also provides the use of an antibody, or antigen-bindingfragment thereof, of the invention to detect MAP in a human or animalfood sample or environmental sample.

The food sample may be a sample of a food product such as milk or otherdairy product or a meat product. MAP infection is known to be widelypresent in domestic livestock including dairy and beef cattle, sheep andgoat flocks as well as farmed deer. The infection is known to besystemic and as the present technology has confirmed, these pathogenscan be abundantly present in blood even in the absence of clinical signsor the presence of positive conventional diagnostic tests such as ELISA.A particular feature of MAP infection is the passage of MAP laden cellsinto milk of all species tested, so that offspring are exposed to themore virulent intracellular form of MAP soon after birth, when they aremost susceptible. MAP is more thermostable than M tuberculosis and cansurvive pasteurisation conditions. Human populations are exposed to MAPin retail pasteurised milk supplies. The best test presently availablefor MAP in milk is PCR based which is too technically demanding andcostly for widespread application.

The environmental sample is typically a sample of surface water, riverwater, domestic water, and water treatment plant water, an aerosol, soilor sediment. The technical difficulties which have affected MAP testingof clinical samples also apply to those used in testing MAP in samplesfrom its catchment, between release from an infected animal into theenvironment, to human exposure. The antibodies, antibody fragments andpeptides of the invention may be used to capture and measure MAP.

Peptides

The invention provides immunogenic MAP peptides. The peptide maycomprise amino acids 26 to 71 of SEQ ID NO: 1, or a fragment of thissequence. The fragment typically comprises at least 10 amino acids, suchas at least 11, 12, 13, 14 or 15 amino acids. The fragment may have anupper limit of 20, 25, 30, 35, 40 or 44 amino acids. The fragment may bea fragment of residues 24 to 44 of SEQ ID NO: 1, or may be a longerfragment comprising residues 24 to 44 of SEQ ID NO: 1. Preferredfragments include a fragment consisting of or comprising residues 26 to39 of SEQ ID NO: 1 and a fragment consisting of or comprising residues52 to 68 of SEQ ID NO: 1, such as a fragment comprising or consisting ofresidues 52 to 71 of SEQ ID NO: 1.

The peptide may comprise or consist of amino acids 345 to 359 of SEQ IDNO: 1. The peptide comprising amino acids 345 to 359 of SEQ ID NO: 1 mayhave length of from 16 to 40 amino acids, such as from 20 to 30 or 22 to27 amino acids, for example 25 amino acids and is typically a fragmentof P900.

The invention provides a phosphorylated peptide which comprises aminoacids 26 to 71 of SEQ ID NO: 1 or amino acids 329 to 385 of SEQ ID NO:1, or a fragment of either of these sequences, such as amino acids 345to 371 of SEQ ID NO: 1, in which one or more serine residue and/or oneor more tyrosine residue and/or one or more threonine residue isphosphorylated. Examples of phosphorylated peptides of the inventioncomprise or consist of amino acids 26 to 39 of SEQ ID NO: 1 in which S37is phosphorylated, residues 350 to 359 of SEQ ID NO: 1 in which eitherS357 or S358 is phosphorylated or both S357 and S358 are phosphorylated.A peptide comprising one of these phosphorylated sequences may havelength of from 15 to 40 amino acids, such as from 20 to 30 or 22 to 27amino acids, for example 25 amino acids, and is typically a fragment ofP900. The peptide may be phosphorylated at one or further serine residueand/or at one or more tyrosine residue and/or at one or more threonineresidue. Such longer fragments include a peptide consisting of orcomprising residues 345 to 359 of SEQ ID NO: 1, such as a peptideconsisting of or comprising residues 329-360 of SEQ ID NO: 1.

The peptide of the invention may be modified at the N-terminus and/or atthe C-terminus and/or may be conjugated or coupled to a carriermolecule. Peptides may, for example, be conjugated to a bacterialsaccharide or a carrier protein, such as keyhole limpet hemocyanin(KLH), bovine serum albumin (BSA), human serum albumin (HSA) orovalbumin (OVA). The peptides may be biotinylated at the N-terminal orC-terminal, may be amidated at the N-terminal or C-terminal and/or mayhave a peptide tag added at the N-terminal or the C-terminal. Thepeptide tag may be, for example, a polylysine, such as a branchedpolylysine octamer, or a cell penetrating peptide such as anoligo-arginine (e.g a polyarginine octamer or nonomer). Preferably, thepeptide is biotylated at the N-terminus and has an amide group or abranched polylysine octamer at the C-terminus. One or more additionalamino acid residues may be added at the N-terminus and/or theC-terminus, optionally in addition to other terminal modifications. Forexample, one or more, such as two, alanine residues may be added at theN-terminus to increase immunogenicity and specificity and/or chargedresidues, for example GKK may be added at the N-terminus or preferablythe C-terminus to reduce hydrophobicity. Where residues, such as GKK,are added at one terminus, the mirror image residues, such as KKG, maybe added at the other terminus.

The present invention also provides polynucleotides encoding thepeptides and antibodies of the invention, as well as expression vectorscomprising such polynucleotides and host cells comprising suchexpression vectors.

Uses of Peptides

The peptides of the invention may be used to generate antibodies for usein the present invention. The invention provides a peptide according tothe invention for use as an immunogen.

The invention provides a method of generating an antibody thatspecifically binds to MAP P900, which method comprises administering apeptide of the invention to a laboratory animal to generate an immuneresponse and isolating antibodies from the animal. The animal may, forexample, be a mouse, rabbit, rat, goat, donkey, alpaca. The method mayfurther comprise screening the isolated antibodies. The isolatedantibodies may be screened for specific binding to MAP P900 bydetermining whether the antibodies bind to a peptide of the inventionand whether the antibodies bind to homologous peptides from one or morerelated organisms. A peptide is selected as being specific for MAP P900where it binds to a peptide of the invention but does not bind to thehomologous peptides from related organisms, or binds to the relatedpeptide(s) to lesser extent than to the MAP peptide, for example showing30% or less, 20% or less, 10% or less, 5% or less binding. For example,at least one, such as 2, 3, 4, 5, 6, 7, 8, 9, 10 or more relatedorganisims may be chosen. The related organisms are typically other Mavium sp and may, for example, be selected from M avium spp avium, Mavium ssp sylvat, M avium 2333, M avium chebnae, M porcinum, MRhodesiac, M thermoresistibile, M avium 16 p44, M avium 2285; Mintracellulare; M xenopi, M avium p44, M avium silvaticum, M aviumhominissuis, Liefsonia xyli TR and M avium AF071067. Exemplary peptidesfrom related organisms are described in the Examples.

Hybridomas producing monoclonal antibodies of the invention may begenerated by standard methods.

Antibodies may be screened/validated in any of the following ways:

1. Staining of cultured MAP and related mycobacteria in theirextracellular phenotype.2. Staining of cultured MAP and related mycobacteria in theirintracellular phenotype in cell culture.3. Western blots of MAP and other mycobacterial lysates and developingthe blots.4. ELISA of monoclonal antibody binding to the same peptides in MAP andrelated peptides in other organisms.5. Laser capture microdissection of stained and unstained areas intissues followed by DNA extraction, MAP specific PCR and verification byamplicon sequencing.6. Fluorescence activated cell separation of antibody stained cells andPCR.7. Differential blockade of antibody staining of tissues by theidentical synthetic target peptide and not by unrelated peptides.Exemplary methods are described in the Examples.8. Colocalisation of multiple monoclonal antibodies on submicrometre MAPparticles in the cytoplasm of infected cells.

Medical Uses/Methods of Treatment

The invention provides an antibody or antigen-binding antibody fragmentaccording to the invention for use in therapeutic or diagnostic methodcarried out on the human or animal body. The therapeutic method istypically treatment or prevention of MAP infection in a subject. Thediagnostic method is typically diagnosis of MAP infection.

The invention also provides the use of an antibody or antigen-bindingantibody fragment according to the invention in the manufacture of amedicament for use in a method of treating, preventing or diagnosing MAPinfection.

Also provided by the invention is a method of treating or preventing MAPinfection in a subject in need thereof, which method comprisesadministering to the subject a therapeutically or prophylacticallyeffective amount of an antibody or antigen-binding antibody fragmentaccording to the invention. The subject may have none, one or more ofthe following diseases: Crohn's disease, psoriasis, thyroiditis,Parkinson's disease, type 1 diabetes, arthritis, ankylosing spondylitis,irritable bowel syndrome, ulcerative colitis, inflammatory boweldisease, Alzheimer's disease, multiple sclerosis, sarcoidosis,idiopathic pulmonary fibrosis and/or chronic fatigue syndrome.

The following Examples illustrate the invention.

Example 1: Phases of Development of the Antibodies of the InventionPhase 1. Mapping Mouse Antibody Binding Peptide Domains in P900

99.6% of the MAP genome is virtually identical in DNA sequence andgenetic organisation to those of other M. avium sp which are ubiquitousin the environment and in healthy animals and humans. Therefore, findingunique targets on MAP which are sterically accessible and abundantlyexpressed during intracellular infection in humans is difficult. Of the4,377 ORFs predicted in the MAP genome, the gene encoding IS900 (NCBIaccession: AE016958.1) was selected. IS900 is a DNA insertion element of1451-53 bp discovered by the present inventor and colleagues late in1985 in three Crohn's disease isolates of MAP (E. Green et al NucleicAcids Research 1989; 17: 9063-73). It is present in MAP in 14-18identical copies inserted at highly conserved sites throughout the MAPgenome. This multicopy element has its own promoter, is abundantlyexpressed in humans and contributes to the broad pathogenic phenotype.

The positive strand of IS900 predicts a protein (P900) of 406 aminoacids. Its full length amino acid sequence is unique to MAP but thereare P900 ‘look-alikes’ in closely related mycobacteria and actinomyceteswhich cover most of the P900 molecule.

Full length P900 protein encoded by the positive strand of IS900 istoxic for E. coli cells. A less toxic truncated version consisting ofamino acids 49 to 377 of P900 was made and expressed as the recombinantprotein in E. coli.

Ten mice were immunised with the recombinant truncated P900 proteinadherent to magnetic beads because the free recombinant protein wasfound not induce a satisfactory immune response. The sera from immunisedmice were screened by ELISA against immobilised P900 and 4 positive micewere identified. Spleen cells from these mice were used for hybridomafusion resulting in 10 parental clones. Supernatants from these andtheir successive subclones were screened against a library of 64synthetic 15 amino acid peptides overlapping by 10 amino acids spanningthe truncated P900 amino acid sequence from ELIAAVTTLADGGEV (SEQ IDNO:19) . . . to . . . DRKRTEGKRHTQAVL (SEQ ID NO:20). The antibodieswere all IgM and the clones eventually proved unstable. Despite theinability to obtain the desired monoclonal reagents, 8 peptides orpeptide clusters were identified as immunogenic within the truncatedP900 protein. In the peptide library these involved peptides No.2-VTTLADGGEVTWAID (SEQ ID NO:12), 27-NKSRAALILLTGYQT (SEQ ID NO:21),41-AKEVMALDTEIGDTD (SEQ ID NO:22), 42-ALDTEIGDTDAMIEE (SEQ ID NO:23) anda cluster within the sequence GRISGNLKRPRRYDRRLLRACYLSALVSIRTDPSSRTYYD(SEQ ID NO:24).

Bio-informatics was used to examine these candidate sequences takinginto account: (i) specificity for MAP especially compared withhomologous sequences encoded by DNA insertion elements in closelyrelated M avium sp well known in the art; (ii) predicted location on theexternal surface of MAP accessible to antibodies; and (iii) predictedsites for post translational modifications such as phosphorylation,myristilation, glycosylation, signalling motifs and limited proteolyticcleavage sites which might affect antibody recognition, location withina MAP-infected cell, trafficking, stability, transport and function.

TABLE 1 Examples of peptides similar to A1 A3 and A4 in other organismsPeptide Sequence Organism A1 VTTLADGGEVTWAIDLNAMAP K-10 bovine, all MAP strains reference (SEQ ID NO: 37)including Sheep S397 VTRLADGGEVTWAVD (SEQ M avium 16 p44 ID NO: 25)VATMADGGEVTWAID (SEQ M porcinum ABV59207; M ID NO: 26)Rhodesiae WP014211331.1; M thermoresistible WP040548537VTRLADGGEVTWAVD (SEQ M avium 2285 EUA29312.1; M ID NO:25)intracellulare EUA53942.1; M avium subsp. avium P44 CAA09798.1VTAQADGGDVTWAID (SEQ M xenopi 4042 EUA52288.1 ID NO: 28) A3NLKRPRRYDRRLLRAGYL MAP and M avium (SEQ ID NO: 39)EMBLAAF08611.1 Japan IS1626 NLQRPRRYNRRLLRA (SEQ ID M porcinum NO: 29)NLKRPRRYDRRLLRT (SEQ ID M avium p44 NO: 30) NLHRPKRYNRRLRRV (SEQ IDM avium silvaticum NO: 31) NLHRPKRYNRRLRRV (SEQ ID M avium hominissuisNO: 31) NLHRPKRYDRRLLRA (SEQ ID Liefsonia xyli TR: Q6ACG7 NO: 33)AE016822 A4 YLSALVSIRTDPSSR (SEQ ID MAP NO: 4) YLSALYSIRSDPASR (SEQ IDM porcinum, M thermoresistible NO: 34) YTSALVSVRYDPSSR (SEQ IDIS116/110/902 NO: 35) YLSAQIAIRTDPASR (SEQ ID M avium AF071067 and P44NO: 36)Phase 2. Preparation of Polyclonal Antibodies to P900 Sequences inRabbits and their Testing on Humans and Animals.

Polyclonal Antibody Preparation:

Preferred initial peptides designated A1-VTTLADGGEVTWAIDLNA (SEQ IDNO:37), A2-NKSRAALILLTGYQTPDA (SEQ ID NO: 38), A3-NLKRPRRYDRRLLRAGYL(SEQ ID NO: 39), and A4-YLSALVSIRTDPSSR (SEQ ID NO:4) were identified.These were prepared as synthetic branched octapeptide immunogens onpolylysine cores and used to immunise rabbits. Suitable titres ofpolyclonal antibodies were readily achieved for A1, A3, and A4. A2 wasnot immunogenic the rabbit. A2 was also intracellular in MAP and was notstudied further.

Antibodies in A1 and A3 sera reacting with Freund's complete adjuvant (Mtuberculosis H37Ra, Difco, USA) were abstracted to completion usingexcess antigen. Only Freund's incomplete antigen was used as theadjuvant with A4. Rabbit polyclonal reagents A1, A3 and A4 were appliedin preliminary studies to explore their ability to detect their targetsequences and therefore MAP immunoreactivity in human and animal tissuesand human blood.

MAP Immunoreactivity in Human Tissues:

In an initial study, fresh intestinal mucosal biopsies were obtainedfrom 14 patients diagnosed with Crohn's disease (CD) attending theendoscopy clinic at St Thomas' Hospital, London, UK and 10 controlpatients without inflammatory bowel disease (nIBD) attending forscreening or follow up. Ethical approval was given by the Local EthicsCommittee (EC03/053). Biopsies were embedded in Jung tissue freezingmedium and snap frozen in liquid nitrogen in the endoscopy suite. Theywere then taken to the laboratory where they were coded and stored −80°C. prior to use.

Orientated biopsies were subsequently cut in 6 μm sections and mountedon PTFE coated slides and stained with A1, A3 and A4 polyclonalantibodies at a dilution of 1:400 to 1:800. Host cell phenotypic markerswere CD3 for T cells, CD8 for monocytes/macrophages, CD19 for B cells,CD66b for neutrophils, CD83 for Dendritic cells, PgP9.5 for Glial cellsand CD31 for endothelium. Secondary antibodies were rabbit anti-mouseTRITC (R0270 Dako, UK), rabbit anti-mouse FITC (F0261, Dako), swineanti-rabbit TRITC (R0156, Dako), swine anti-rabbit FITC (F0205, Dako)and goat anti-mouse FITC (F0479). Slides were washed ×3 in PBS andmounted in Fluoromount agent (F4680 Sigma-Aldrich, UK) followed by acoverslip.

Use of antibodies A1, A3 and A4 alone at concentrations of 1:500 to1:800 resulted in staining of cells within the epithelium and in theunderlying lamina propria. Antibodies were then used in pairs with A1labelled with TRITC (red) and A3 or A4 with FITC (green).

The A1 site is located on the extracellular aminoterminal domain of theP900 protein adjacent to the first transmembrane region and right upagainst the surface of the microbial cell. The A1 peptide appeared toremain attached to MAP.

The A3 and A4 sites are located at the centre of the longercarboxyterminal extracellular domain either side of Cysteine 344. Thecarboxyterminal domain may either be attached or released by limitedproteolytic cleavage close to the second transmembrane region.

Use of A1 (red) and A4 (green) with the carboxyterminal peptide stillattached resulted in colocalisation (gold) not only in the same cellsbut also on submicrometre particles within the cytoplasm of infectedcells. Release of the carboxyterminus resulted in a progressive gradientof colour change from gold to orange to red and the visible migration ofthe released peptide (green) in the cytoplasm of the affected cell.Other cells were seen to contain green only suggesting the ability ofreleased carboxyterminal peptide to traffic to other cells which did notthemselves contain MAP. This was supported by the appearance in tissuesof intercellular vesicles filled green consistent with endosomes.

In the surface epithelium MAP was seen to infect enterocytes as well asintra-epithelial cells consistent with lymphocytes and macrophages. MAPwas seen to cluster often in a ‘necklace’ around the base of the mucusvacuole of goblet cells releasing green carboxyterminal peptides whichmigrated in the cytoplasm to the apex of these cells as well as withinthe mucus vacuole itself.

MAP was also seen to infect cells widely in the lamina propria andparticularly clusters of cells around the bases of crypts. Staininginvolved particularly macrophages, polymorphs and B-lymphocytes but notT-lymphocytes although the presence of T-lymphocytes adjacent to MAPclusters was frequently noted.

Abundant MAP infection in endoscopic mucosal biopsies was seen in all 14patients with Crohn's disease. Scant clusters of immunoreactive MAP wereseen in 8 out of the 10 control subjects. The other 2 control subjectscontained no MAP staining at all. The addition of specific peptide tothe operational buffer completely blocked staining of tissues by thecorresponding antibody. Use of other peptides had no effect on antibodybinding. Together with colocalisation this specific blockade reinforcedthe precision and specificity of the MAP detection system.

PCR Verification of A1 Antibody Binding to MAP in Human Tissues:

Laser microdissection pressure catapulting (LMPC) of A1 immunoreactiveloci was carried out to determine whether antibody recognition intissues equated with the presence of MAP using IS900 PCR. Freshendoscopic mucosal biopsies were obtained from 11 consenting patientsand 4 control subjects without inflammatory bowel disease. Tissues weresnap frozen in liquid nitrogen and 6 μm cryostat sections were cut aspreviously described. Sections were transferred to PTFE-coatedmicroscope slides for routine H&E staining. Those for LMPC wereimmobilised on PEN-membrane slides (Carl Zeiss MicroImaging GmbH,Germany).

Immunoreactive MAP regions were identified in sections with A1 rabbitpolyclonal antibody using biotinylated alkaline phosphatase H tagged2^(nd) antibody to rabbit immunoglobulin. After washing slides in PBS,Vectastain Universal ABC-AP kit (Vector Laboratories UK) was used forlocalisation of immunoreactive MAP regions according to themanufacturer's instructions. Secondary antibodies were localised usingthe Vector Blue Alkaline Phosphatase Substrate Kit 1 (VectorLaboratories UK).

Lasermicrodissection and pressure catapulting was used to isolateimmunoreactive (IR) and non-immunoreactive (nIR) MAP regions using theZeiss PALM MicroBeam Laser microdissection system. Prior tomicrodissection, particular care was taken to ensure that sections werecompletely air dried so that excised regions readily detached. IR andnIR regions were identified visually and the adhesive cap tubepositioned above the selected area. Samples were accumulated onto thecap of the adhesive tube. DNA extraction was carried out as described(T. Bull et al. 2003 J Clin Microbiol 2003; 41:2915-23). Briefly, 200 μLof Mycobacterium Lysis Buffer (MLB), 8.6 ml molecular-grade water, 800μL, 5M NaCl, 1M 10× Tris-EDTA (TE) and 600 μL, 10% SDS was added to eachtube and incubated overnight at 37 deg C. 104, of 10 mg/ml Proteinase K(Sigma), 54, of 100 mg/ml Lysozyme (Sigma) and 44, of 120 mg/ml Lipase(Sigma) in MLB were added to each tube and incubated at 37° C. for afurther 3 hours. Samples were transferred to Lysing Matrix B ribolysertubes and 400 μL, 1×TE added. Tubes were mechanically disrupted at 6.5ms² for 45 seconds on a FastPrep Ribolyser instrument. Standardphenol-chloroform-isoamyl DNA extraction procedure was carried out.Purified DNA was resuspended in 50 μL 1×TE. Nested PCR using 24, oftemplate DNA was carried out using L1 and L2 first round primers and AV1and AV2 second round primers. The expected 298 bp PCR amplicon wasvisualised using 1% agarose gel electrophoresis. Stringent precautionswere taken as described to exclude amplicon contamination.

All 4 control subjects tested negative by IS900 PCR. Immunoreactiveregions from 7 of the 11 patients in the CD group were positive for MAPby IS900 PCR, confirmed by amplicon sequencing in 5. All the nIR regionssampled in CD patients were PCR negative. All 7 patients testingpositive for MAP by IS900 PCR were undergoing treatment withazathioprine alone. The 4 PCR negative samples came from Crohn's diseasepatients receiving treatment with azathioprine in combination withHumira or 6-mercaptopurine and Infliximab.

MAP Detection in Formalin-Fixed Paraffin-Embedded Histopathology Blocks:

The ability of the diagnostic system for MAP in tissues to operate onroutine fixed paraffin embedded histopathology samples substantiallyfacilitates its clinical and commercial application. Furthermore itallows the test to be applied retrospectively to archive materials sothat, with appropriate approvals, substantial numbers of patients andtheir tissue samples can be screened and answers to such questions asthe prevalence of MAP infection in populations at risk as a whole can beinvestigated economically. Antibody binding to synthetic peptidesequences is sequence dependent rather than conformation dependent,enabling the method to operate successfully on such samples.

The protocol for antigen retrieval and immunostaining of paraffinembedded tissue sections using the rabbit polyclonal antibodies wasoptimised as follows as follows: 0.2 μm tissue sections werede-paraffinised for 10 mins in 3 changes of xylene, rehydrated indescending grades of alcohol and placed in tap water for 5 mins. Antigenretrieval was achieved by immersing slides in distilled water containing0.05% protease XIV Streptomyces Griseous Sigma P6911 P code 1000984453at 37° C. for 5 mins. Slides were allowed to cool to room temperatureand washed 3 times in 1×PBS each for 5 mins. Non-specific Fc receptorbinding was blocked using Trustain @ 1/50 for 15 mins, and if requiredpermeabilised in 0.1% Triton X-100 for 5 mins. Sections were washedbriefly in 1×PBS and then incubated in primary antibody solution for 1hour at room temperature on an orbital shaker. Sections were washedthree times in 1×PBS each for 5 mins and incubated in secondary antibodyconjugated with Dylite488/550 @ 1/1000 for 45 mins at room temperature(RT). Sections were washed three times in 1×PBS each for 5 mins,dehydrated, cleared in Xylene, mounted in aqueous mountant (Vectashield)and cover slipped.

Phase 3. Preparation of Murine Monoclonal Antibodies to Optimised P900Peptide Sequences within the Selected A0, A1, A3 and A4 Sites andPhosphorylated Derivatives.

At this stage, an additional target site for monoclonal antibodyproduction designated A0 was introduced comprising the sequenceMVINDDAQRL (SEQ ID NO: 40), residues 26-39 in the extracellularaminoterminal domain of P900. Few identical matches to this sequencewere found in NCBI databases.

The production of murine monoclonal antibodies was first attempted inthe following manner. Immunogen peptides in each case incorporating asolitary Cys thiol for linkage to KLH were prepared for A0(MVINDDAQRL-C)(SEQ ID NO: 41), A3 (C-NLKRPRRYDR)(SEQ ID NO: 42) and A4(C-VSIRTDPSSR)(SEQ ID NO: 43) and 5 mice were immunized in each group.Despite good immunological responses in some of the mice in each group,no monoclonals recognising their native targets in tissues wereobtained. This was found to be due to the exclusive use of the targetpeptide for screening ELISAs and clonal selection being coated directlyon to ELISA plate wells. This resulted in substantial artifact and theproject was a comprehensive failure.

On the other hand the inventor found that it was essential for thetarget synthetic peptides used in screening ELISAs to be alpha-nBiotinylated and attached to wells coated with streptavidin. Thisincreased the steric accessibility of the attached mobile peptides andpermitted the adoption of the appropriate configuration of the peptidefor antibody in the liquid phase. There was close correlation betweenantibody binding to target peptide in this form in ELISAs and to thenative peptide in target tissues.

The essential Streptavidin coating and Biotinyl-peptide immobilisationin ELISA wells was adopted and used throughout the next project. Duringthis project, mouse sera and culture supernatants were selected forbinding to Reference peptide but not Negative peptides. Selected sampleswere subsequently tested by immunofluorescence on human and animaltissues and cells infected with MAP.

Immunogens were synthesised using the peptide sequences A0XMVINDDAQRLLSQR-C(SEQ ID NO: 44), A1 VTTLADGGEVTWAID-C(SEQ ID NO: 45),and XA4 YLSALVSIRTDPSSR-C(SEQ ID NO: 46) in each case the Cys thiol wasused to link to KLH using standard methods. These constructs were usedto immunise groups of 5 to 10 BalbC mice. Good serological responses toimmunisation occurred in all groups and promising candidate clones wereobtained for each group. Despite additions to immunisation protocolsincluding in vitro immunisation and follow on immunisation usingdifferent immunogen adducts together with much additional work, nosuitable final stable IgG clones could be obtained.

The materials used initially in the next project were as follows:

Immunogen Peptide A0 ac-MVINDDAQRL-8branchedPolylysineOctamer (SEQ IDNO: 47) Reference peptide Biotinyl-MVINDDAQRL-amide (SEQ ID NO: 48)Negative peptide 1 Biotinyl-MVINDDLQR-amide (SEQ ID NO: 49)Negative peptide 2 Biotinyl-MVINNDAE-amide (SEQ ID NO: 50)Immunogen peptide A1 ac-VTTLADGGEVT-8branchedPolylysineOctamer (SEQ IDNO: 51) Reference peptide Biotinyl-VTTLADGGEVT-amide (SEQ ID NO: 52)Negative peptide 1 Biotinyl-VATMADGGEVT-amide (SEQ ID NO: 53)Negative peptide 2 Biotinyl-VTRLADGGEVT-amide (SEQ ID NO: 54)Immunogen peptide A3 ac-NLKRPRRYDR-8branchedPolylysineOctamer (SEQ IDNO: 55) Reference peptide Biotinyl-NLKRPRRYDR-amide (SEQ ID NO: 56)Negative peptide 1 Biotinyl-NLKRPRR-amide (SEQ ID NO: 57)Negative peptide 2 Biotinyl-NLRRPRRYHR-amide (SEQ ID NO: 58)Negative peptide 3 Biotinyl-NLHRPRRYHR-amide (SEQ ID NO: 59)Negative peptide 4 Biotinyl-NMRRPRRYNR-amide (SEQ ID NO: 60)Negative peptide 5 Biotinyl-NLRRPKRYNR-amide (SEQ ID NO: 61)Negative peptide 6 Biotinyl-NLQRPRRYNR-amide (SEQ ID NO: 62)Immunogen peptideA4 ac-VSIRTDPSSR-8branchedPolylysineOctamer (SEQ ID NO: 63)Reference peptide Biotinyl-VSIRTDPSSR-amide (SEQ ID NO: 64)Negative peptide 1 Biotinyl-VSIRTDP-amide (SEQ ID NO: 65)Negative peptide 2 Biotinyl-SIRSDPSSR-amide (SEQ ID NO: 66)Negative peptide 3 Biotinyl-YSIRSDPASR-amide (SEQ ID NO: 67)Negative peptide 4 Biotinyl-VSVRYDPSSR-amide (SEQ ID NO: 68)Negative peptide 5 Biotinyl-IAIRTDPASR-amide (SEQ ID NO: 69)

Groups of 5 Swiss Webster mice were immunised with the immunogen peptideconstructs in Freund's Complete Antigen on day 1 followed by 2 boostershots on day 14 and day 21 using Freund's Incomplete antigen. Boostingwas continued but it was clear that none of the 4 groups were respondingsatisfactorily. Fresh peptide immunogens ac-MVINDDAQRL-C(SEQ ID NO: 70),ac-VTTLADGGEVT-C(SEQ ID NO: 71), ac-NLKRPRRYDR-C(SEQ ID NO: 72), andac-VSIRTDPSSR-C(SEQ ID NO: 73) were synthesised, coupled via the C- toKLH and immunisations continued.

Transient responses in the A0 and A1 groups were not sustained. Bothflatlined and were terminated.

Serum from one mouse in each of the A3 and A4 groups achieved asufficient titre to proceed to fusion and development of parentalclones. A satisfactory subclone was not subsequently obtained for A3 andthis project was terminated. A satisfactory subclone was achieved for A4which recognised the reference peptide and none of the 5 negativepeptides and was taken through final production and Protein A affinitypurification.

At this stage three further modifications were introduced into theprotocol:

-   -   1. The use of Balb/C mice.    -   2. Adoption of the technique of administering the immunogen at        the base of the tail vein followed by direct fusion of pooled        cells from inguinal lymph nodes.    -   3. Redesigned projects with the following new peptide        immunogens.

Immunogen peptide AOX C-MVINDDAQRLLSQR-amide (SEQ ID NO: 74)Reference peptide Biotinyl-MVINDDAQRLLSQR-amide (SEQ ID NO: 75)Negative peptide 1 Biotinyl-MVINDDLQRIILFL-amide (SEQ ID NO: 76)Negative peptide 2 Biotinyl-MSINDDAQKLKDRL-amide (SEQ ID NO: 77)Immunogen peptide AOXP C-MVINDDAQRLL[pS]QR-amide BSA conjugated (SEQID NO: 78) Reference peptideBiotinyl-MVINDDAQRLL[pS]QR-amide (SEQ ID NO: 79) Negative peptide 1Biotinyl-MVINDDAQRLLSQR-amide (SEQ ID NO: 80) Immunogen peptideXA1 ac-AAVTTLADGGEVTWAIDGKK-C BSA conjugated (SEQ ID NO: 81)Reference peptide Biotinyl-KKGAAVTTLADGGEVTWAID-amide (SEQ ID NO: 82)Negative peptide 1 Biotinyl-KKGAAGTTLADGGEVTWAID-amide (SEQ ID NO: 83)Negative peptide 2 Biotinyl-KKGSTVATMADGGEVTWAID-amide (SEQ ID NO: 84)Negative peptide 3 Biotinyl-KKGQAVTRLADGGEVTWAVD-amide (SEQ ID NO: 85)Negative peptide 4 Biotinyl-KKGFEVTTLADGTEVATSPL-amide (SEQ ID NO: 86)

The addition of the two Alanine residues to the amino terminus at thissite was designed to increase immunogenicity and specificity. Theaddition of the charged -GKK residues at the carboxy terminus of theimmunogen peptide was designed to overcome its increased hydrophobicity.In the event that the immunogen peptide formed micelles during thecoupling reaction the presence of the charged GKK moiety adjacent to theCysteine thiol would favour its accessibility to the BSA. The inclusionof mirror image KKG—at the amino terminus of the reference peptide wouldfavour the selection of antibody specific for the target sequence itself

Immunogen peptide XA4P C-YLSALVSIRTDPS[pS]R-amide BSA conjugated (SEQID NO: 87) Reference peptideBiotinyl-YLSALVSIRTDPS[pS]R-amide (SEQ ID NO: 88) Negative peptide 1Biotinyl-YLSALVSIRTDPSSR-amide (SEQ ID NO: 89) Negative peptide 2Biotinyl-YLSALYSIRSDPA[pS]R-amide (SEQ ID NO: 90) Negative peptide 3Biotinyl-YLSALVSVRYDPS[pS]R-amide (SEQ ID NO: 91) Negative peptide 4Biotinyl-YLSAQIAIRTDPA[pS]R-amide (SEQ ID NO: 92)

All five A0X, A0XP, XA1, A4 and XA4P projects incorporating clonalselection for Reference peptide recognition by ELISA with limited or nobinding to Negative Control peptides, followed by tissue and cellstaining by selected clonal supernatants binding to tissues and cells,have been brought to successful conclusions. Affinity purified A0X,A0XP, XA1, A4 and XA4P monoclonals were obtained.

Example 2: Uses of the Diagnostic Technology for the Detection andCharacterisation of MAP Infections in Samples from Humans and Animalsand in Food Safety 1. Detection and Measurement of MAP Infecting HumanGut Tissues

Endoscopic biopsies were studied from 45 people with Crohn's disease andsome other disorders such as Irritable Bowel Syndrome (Scanu et al.Mycobacterium avium subspecies paratuberculosis infection in cases ofIrritable Bowel Syndrome and comparison with Crohn's disease and Johne'sdisease: common neural and immune pathogenicities. J Clin Microbiol2007: 45:3883-90). Samples were immediately fixed in formalin, followedby standard processing and embedding in paraffin Histopathology blocks.Preliminary work was carried out which identified 2 μm sections asoptimal. Sections were treated with a standard antigen retrievalprotocol. They were then stained with dilutions of monoclonal antibodiesin the range 1 in 500 to 1 in 5000. Both direct fluorophore labelling ofprimary antibodies as well as the use of secondary antibodies labelledwith fluorophore were employed. Tissues were stained with each of theprimary antibodies A0X, A0XP, XA1, A4, XA4P used alone and viewed withusing a Zeiss AxioSkop 2 microscope at magnifications of ×100 and ×200to obtain a general impression of the distribution of MAP and thensubsequently at ×400 and ×1000. MAP in humans is a Ziehl-Neelsen (Z-N)staining negative form and appears to be in the size range 0.3-1 μm.Higher magnification is required for satisfactory resolution.

A0X, XA1, A4 and XA4P all stained MAP in human gut, more specifically inendoscopic biopsies of the gut in all of the 45 people with Crohn'sdisease tested. However, staining of human gut tissues by A0XP was notseen in humans other than the occasional fluorescent signal from thelumen of a tissue blood vessel containing an A0XP positive cell in theblood. Unlike in animals, phosphorylation of A0X does not appear tooccur widely in human gut. Phosphorylated A0XP however is seen in humanblood in MAP infections. Staining of MAP by A0X, A0XP, XA1, A4 and XA4Pis seen in human blood in MAP infection and in all people with Crohn'sdisease tested.

Antibodies were also used in combinations and viewed by confocalmicroscopy. Preferably antibodies were used in pairs. Preferred pairswere A0X with A0XP or XA1 from the amino terminus of the parent MAPmolecule, and A4 with XA4P from the carboxyterminal end. Preferred pairswere also A0X with A4 and XA1 with A4 labelled with a red or greenfluorophore respectively. This provided gold staining when the reagentscolocalised specifically in the cytoplasm, not only of the same cells,but on the sub-micrometre MAP particles within the cytoplasm of infectedcells. Such colocalisation provided strong confirmation of thespecificity of MAP detection.

The use of antibody pairs comprising XA1 with A4 and A0X with A4revealed a further aspect of the method. This is because whereas A0X andXA1 appeared to remain attached to the MAP organism itself or releasedto remain in the cell or displayed on the cell surface, A4 is frequentlyreleased from MAP to become displayed on the cell surface as well asreleased from the infected cell to traffic between cells. When A0X orXA1 are labelled with a red fluorophore and A4 labelled with a greenone, the original gold colocalisation is progressively depleted toorange, and then to red as the green labelled A4 traffics to and entersother cells. Membrane bound structures filled with A4 green were seen,consistent with the presence of intercellular vesicles.

Biopsy samples from all the patients with Crohn's disease testedpositive for MAP. This was observed in cells of the mucosal compartment,particularly the basal portion of the epithelial cells and the cytoplasmsurrounding the basal portion of the mucus in goblet cells. Other MAPcontaining cells in the mucosal compartment were intra-epithelialmacrophages and dendritic cells as well as intra-epithelial lymphocytes.MAP containing cells and free bacilli were also observed in the luminalmucus gel layer. In the lamina propria MAP infection was common inmacrophages, polymorphs and B-lymphocytes. T-lymphocytes were rarelyseen to be involved themselves, but frequently occurred adjacent to MAPfilled macrophages. MAP positive cells were frequently seen in the lumenof small blood vessels. In duodenal biopsies MAP staining of Brunner'sglands was limited only to the occasional macrophage filled with MAPwhile the glandular cells themselves were unaffected. However MAPcontaining cells were present in the interstitial connective tissue ofBrunner's glands. A0XP in cells within tissues appeared to concentratearound the nucleus. These images of MAP in human tissues can be adaptedto become quantitative and enable monitoring of the MAP infective load.

Surgical resection samples were also available from 4 patients withCrohn's disease. These samples permitted the examination not only thedeeper layers of the gut through to the serosa, but also larger bloodvessels, lymphatic vessels, extra intestinal fat wrapping and regionallymph nodes in the gut mesentery. As with the biopsy tissues the mucosaand sub-mucosa of each of these 4 patients were strongly positive forMAP. It was also found that the MAP infection extended right through thewall of the gut involving lymphatic vessels, the tissue between musclelayers and the serosa itself. In some sections lymphatic vessels full ofstained MAP organisms were seen.

It has long been known that one of the pathological features of Crohn'sdisease is a vasculitis deemed to be autoimmune. The diagnosticantibodies showed that the thickened walls of such blood vessels wereextensively infiltrated with MAP which also involved the surroundingperivascular connective tissues. Another characteristic pathologicalfeature of Crohn's disease is the increase in fatty tissue around thegut. This is particularly well seen in the terminal ileum where it istermed ‘fat wrapping’. The adipocytes of this fat are known to be a richsource of the inflammatory marker CRP (C-reactive protein). Thediagnostic method showed that the thin cytoplasm of the adipocytes inthis tissue were extensively infected with MAP. Abundant MAP was alsoseen in cells of the interstitial connective tissues within the fat. MAPwas also seen to involve regional lymph nodes.

The gut tissues of all 5 people diagnosed with Irritable Bowel Syndrome(IBS) who were tested were also seen to be widely infected with MAP in amanner very similar to CD. Positive MAP staining of gut endoscopicbiopsies was also seen in cases of Thyroditis and Psoriasis.

2. Animal gut tissues

Gut tissue samples were studied from 3 cows, 1 sheep, 1 goat, 1 red deerand 2 fallow deer all diagnosed with Johne's disease (JD). Autopsysamples were processed and stained with the primary antibodies, asdescribed for humans. Tissues from all the animals were extensivelyinfected with MAP which was generally present in the Ziehl-Neelsenpositive phenotype. MAP in the guts of these animals diagnosed withJohne's disease stained with the A0X, A0XP, A4 and XA4P antibodies aswell as with XA1. The microscopic appearance of MAP in animals wasusually that of the classical Z-N positive mycobacterial phenotype butthe monoclonal antibodies of the present work also demonstrated thepathogens in the paucimicrobial form.

The infective load of MAP in animals with Johne's disease was heavierthan that found in humans in keeping with the well-recognised commonpluribacillary form of JD. The MAP phenotype itself was consistent withZN-positive cells. There was extensive involvement of mucosa and laminapropria and all layers of the gut. Cords of cells were seen whichresulted from microvasculature full of MAP infected leucocytes. Inaddition, the thickened walls of vasculitic blood vessels andperivascular tissues were infiltrated with MAP infected cells as wasseen in humans. MAP infection was also seen in neurovascular bundlesaffecting ganglion cells as well as nerve sheathes. This is consistentwith the well described damage to the enteric nervous system of animalsdiagnosed with JD, much as in humans diagnosed with CD. A conspicuousdifference between the gut tissues of these 5 ruminant species andhumans is that A0XP is widely present in these animal gut tissues butappeared to be absent from human gut tissues.

3. Human Blood

Unlike in human gut tissues, A0XP, the phosphorylated form of A0X, iswidely expressed in human blood. A0XP (MVINDDAQRLL[pS]QR (SEQ ID NO: 3))is the Serine phosphorylated form of A0X peptide in the extracellularamino terminal region of the IS900 protein. XA4P (YLSALVSIRTDPS[pS]R(SEQ ID NO:6)) is the A4 peptide in the extracellular carboxyterminalregion of the IS900 protein with the distal of its two adjacent Serineresidues phosphorylated. In CD both A0XP and XA4P are expressed withinand on the surface of MAP-containing cells in human blood.

This provides 2 pairs of sterically accessible mutually exclusiveantibodies on the P900 polypeptide for use in flow cytometry withA0X/A0XP on the amino terminal extracellular domain and A4/XA4P on thecarboxy terminal extracellular domain. Each pair exists in a dynamicequilibrium as substrate and product, the sum of which provides a robustsignal for determining the percentage of peripheral blood leucocytepopulations infected with intra-cellular MAP. A0X/A0XP either remainattached to MAP or can be released within the cell and on the infectedhost cell's surface. A4/XA4P provide a similar signal but A4 can exitMAP infected cells and traffic between cells so that the cellpopulations containing A4/XA4P comprise those containing MAP organismswith an additional smaller population in which the A4/XA4P has beenacquired by inter-cellular trafficking.

Flow cytometry on routine EDTA clinical blood samples was performed on42 people with Crohn's disease using direct fluorophore labelledA0X-FITC/A0XP-PC5.5 and A4-FITC/XA4P-PC5.5 in an exploratory study. Allpeople tested positive for MAP, with the proportion of the totalcirculating white blood cell population positive for MAP ranging from3.9% to 47.1%. Use of phenotypic markers of the principal blood celllineages enables a breakdown according to host cell type. Theseproportions were generally greater with A4/XA4P than they were withA0X/A0XP. The ratios A0X/A0XP and A4/XA4P provided a measure ofphosphorylation activity. A high ratio of XA4P/A4 tended to characterisepeople with Crohn's disease in a higher state of activity. In suchpeople intact monocytes in blood completely coated with segregatedmasses of A4/XA4P could be seen.

A second flow cytometry was carried out in 24 consecutive patients withCrohn's disease to determine the proportion (%) of total circulatingwhite blood cells containing MAP.

Blood samples were collected into standard EDTA Vacutainer tubes. 1000of blood was then added to the required number of 12×75 mm roundbottomed Falcon tubes. These were incubated for 5 minutes with 50 HumanSeroblock (Bio-Rad). Anti-human CD45 APC conjugated antibody (BeckmanCoulter) was added to all tubes to enable gating on the leucocytepopulations. Half of the tubes (labelled ‘surface stained’) were thentreated with the anti-MAP monoclonal antibodies for 15 minutes at roomtemperature in the dark. 0.5 mls OptiLyse C (Beckman Coulter) red bloodcell lysis buffer was then added to all these tubes and incubated for 10minutes at room temperature in the dark. The cells were then washed byadding 0.5 mls of PBS and centrifuged at 325G for 5 minutes and thesupernatant discarded.

All tubes were then fixed with 1000 Fixation Medium A (Thermo FisherScientific) for 5 minutes then washed as above. The tubes that had notbeen stained with anti-MAP antibody (labelled ‘Permeabilised’) wereincubated with Invitrogen Permeabilised Medium B (Thermo FisherScientific) to the pellet, anti-MAP monoclonal antibodies were added andincubated for 15 minutes at room temperature in the dark, followed byPBS washing as above. All tubes were then made up to 1 ml with flowbuffer (PBS (Ca and Mg free), 0.2% sodium azide and 2% Bovine SerumAlbumin (BSA). The samples were then acquired on a CytoFLEX flowcytometer (Beckman Coulter) gated on SSC vs CD45 and subsequently thedata was an analysed using CytExpert software (Beckman Coulter).

The results of the second study in 24 people with Crohn's disease areshown in the table below (Table 2). There were 8 women and 16 menbetween the ages of 18 and 49 years. The numbers in the table along therows indicate the % of the total circulating white blood cell populationin each person stained by the corresponding MAP antibody A0X alone, A0XPalone or both A0X+A0XP as well as A4 alone, XA4P alone or both A4+XA4P.Because the A0 antibodies remain attached to their target peptides forlonger than the A4 antibodies, the SUM of the A0 data in an individualperson were taken as the measure of the % of circulating WBCs containingMAP (highlighted centre column). This SUM varies with the progress,clinical course and responses to treatment of Crohn's disease providinga direct access to the contribution to pathogenicity made by this uniquemulticopy insertion element.

The Flow Cytometry data from A4, XA4P and A4+XA4P provides a seconddirect insight into a probable contribution to pathogenicity of MAP byrecording a further aspect of the in vivo function of P900. This is theability to observe the phosphorylation and trafficking of the attachedand released carboxy terminus both with the phosphorylation of thedownstream serine as in the present work and that of the upstreampartner and the presence and effect of dual phosphorylation.

Table 1 summarises the Flow Cytometry data obtained from 24 patientswith Crohn's disease based on the use of the monoclonal antibodies A0Xand A0XP on the extracellular amino-terminus of P900 on the left of thetable and A4 and XA4P on the extracellular carboxy-terminus of P900 onthe right. The data for each patient in each row separate into bindingto the surface of white blood cells (surf) and binding to wholepermeabilised cells (perm). The total proportion of cells infected byMAP is given by the sum of the percentages % in separate permeabilisedcell populations identified by A0X alone, A0XP alone and A0X+A0XP(highlighted). This is the preferred measurement because A0X peptidestend to remain bound to the host intracellular mycobacterial cellslonger than A4 peptides. On the right of the table are the results usingA4, XA4P and A4+XA4P stained cell populations. In this study thestrongly predicted phosphorylation of the distal serine in XA4P is usedbut similar studies may target the phosphorylated proximal serine of thepair or in dual phosphorylation.

The potential of the data comes together when we look at detail. The %total MAP loading across the group of 24 patients ranges from 1.52% to48.9% and appears at the present stage to vary with the activity of thedisease. Peaks or troughs in the % of MAP positive cells may follow theonset of anti-MAP treatments. More data will come as larger numbers ofpeople are tested and with different diseases particularly in the“autoimmune and auto inflammatory” group, and with access to the loadingof individual cell types. More data will also be obtained from studyingthe clinical correlates of phosphorylation events and monitoring theeffects of different treatments.

The data show that the proportion of cells with A0X/A0XP or both ontheir surfaces is about half. In the permeabilised cells, the total cellpercentage with A0X/A0XP is in close agreement with that using A4/XA4P,whereas the sum of A4/XA4P on the cell surface is considerably less thanwith A0X/A0XP. This would be consistent with a greater loss of A4/XA4Pfrom the cell surface which is in keeping with its recognised greatermobility. Studies of the effect of these phosphorylation events willrequire larger clinical studies.

The flow cytometry system is the first example to be developed forparatuberculosis infection in Crohn's disease. This can now be used tostudy MAP infection in other diseases including especially psoriasis,thyroiditis, Parkinson's disease, type 1 diabetes, arthritis, ankylosingspondylitis, irritable bowel syndrome, ulcerative colitis, inflammatorybowel disease, Alzheimer's disease, multiple sclerosis, sarcoidosis,idiopathic pulmonary fibrosis and/or chronic fatigue syndrome. WithCrohn's disease as with these other diseases, particularly “autoimmuneconditions”, whether or not the presence of MAP is contributing todisease causation or progression will come from whether or not specificanti-MAP therapy leads to remission or healing of the disease. Atpresent, the therapeutic T-cell vaccine against MAP is in early clinicaltrials.

TABLE 2 MAP Monoclonal A0X A0XP A0X + A0XP A0X/A0XP A0X A0XP A0X + A0XPA0X/A0XP A4 Patient M/F Age surf surf surf SUM perm perm perm SUM surf 1F 32 5.67 0.7 1.49 7.86 25.02 2.93 1.11 29.06 3.14 2 M 48 2.37 4.94 4.8512.16 7.52 12.42 10.87 30.81 5.47 3 M 29 7.59 0.05 1.30 8.94 7.66 5.718.33 21.70 3.09 4 M 28 1.50 0.19 3.07 4.76 4.90 1.12 0.29 6.31 3.54 5 M37 0.90 0.77 1.37 3.04 11.02 10.33 0.19 21.54 0.31 6 F 40 16.15 0.760.37 17.28 20.62 0.30 0.76 21.68 1.20 7 F 25 10.43 0.38 0.73 11.54 23.130.41 1.09 24.63 2.59 8 M 39 1.32 6.62 2.08 10.02 2.32 8.12 5.01 15.458.35 9 M 20 37.93 0.17 0.02 38.12 45.82 0.44 1.83 48.09 0.41 10 M 3314.81 1.45 0.31 16.57 23.05 2.88 13.98 39.91 21.26 11 F 48 3.95 1.8 1.497.24 4.92 1.97 1.71 8.60 2.20 12 F 26 1.06 0.74 1.89 3.69 2.39 1.65 2.006.04 0.45 13 M 27 1.39 1.65 2.00 5.04 3.42 2.61 2.02 8.05 2.17 14 M 292.28 2.3 1.86 6.44 2.31 5.01 2.36 9.68 0.30 15 M 29 1.95 12.86 4.9919.80 3.40 15.85 5.71 24.96 0.00 16 M 25 0.02 1.32 0.03 1.37 0.11 1.410.00 1.52 0.68 17 M 37 0.24 0.33 0.05 0.62 11.40 11.39 5.81 28.60 0.0518 M 18 1.26 1.96 6.63 9.85 1.78 3.41 5.39 10.58 0.36 19 F 48 1.79 2.792.96 7.54 2.62 5.96 5.15 13.73 1.04 20 F 18 0.92 5.15 0.64 6.71 1.225.67 1.20 8.09 5.12 21 M 20 11.78 0.36 8.85 20.99 15.41 0.30 9.28 24.990.85 22 M 49 0.35 1.27 0.80 2.42 1.58 1.97 2.76 6.31 8.80 23 M 19 0.770.68 3.83 5.28 1.76 1.72 4.01 7.49 0.38 24 F 48 0.05 4.09 0.02 4.16 0.946.83 0.21 7.98 0.00 SUM 231.44 425.80 average 9.64 17.74 MAP MonoclonalXA4P A4 + XA4P A4/XA4P A4 XA4P A4 + XA4P A4/XA4P Patient M/F Age surfsurf SUM perm perm perm SUM 1 F 32 6.63 5.98 15.75 3.91 19.76 6.88 30.552 M 48 1.19 0.13 6.79 7.54 1.27 2.29 11.10 3 M 29 3.70 1.44 8.23 9.054.23 2.82 16.10 4 M 28 1.00 0.34 4.88 5.85 0.23 1.25 7.33 5 M 37 1.420.90 2.63 6.85 19.24 2.94 29.03 6 F 40 0.14 0.21 1.55 1.25 2.77 1.885.90 7 F 25 0.14 0.50 3.23 2.89 12.09 31.62 46.60 8 M 39 8.73 6.09 23.1711.92 10.83 12.83 35.58 9 M 20 0.00 0.12 2.50 19.89 5.76 3.01 28.66 10 M33 0.03 1.23 22.52 7.90 0.84 41.03 49.77 11 F 48 0.02 0.28 2.50 2.354.17 1.72 8.24 12 F 26 0.15 0.10 0.70 2.77 0.96 0.81 4.54 13 M 27 0.960.81 3.94 3.04 1.46 1.35 5.85 14 M 29 6.31 2.50 9.11 2.33 11.74 7.9121.98 15 M 29 0.56 2.45 3.01 0.00 6.98 8.26 15.24 16 M 25 0.64 0.46 1.781.38 1.37 0.47 3.22 17 M 37 2.24 0.14 2.43 2.27 4.31 1.09 7.67 18 M 189.11 1.53 11.00 0.42 13.6 1.76 15.78 19 F 48 3.40 3.60 8.04 2.43 4.888.14 15.45 20 F 18 0.53 2.61 8.26 5.62 0.85 5.61 12.08 21 M 20 2.70 0.363.91 19.92 4.1 6.84 30.86 22 M 49 0.31 7.08 16.19 9.06 0.58 9.12 18.7623 M 19 0.21 0.21 0.80 2.06 0.76 0.41 3.23 24 F 48 6.76 4.62 11.38 0.497.81 4.91 13.21 SUM 174.30 436.73 average 7.26 18.20

3.2 Cytology

Cells isolated from peripheral blood were stained with a combination oftwo directly conjugated monoclonal antibodies: A0X (FITC/Green)+A0XP (Cy5.5/Red) or A4 FITC/Green)+XA4P (Cy 5.5/Red). Confocal images wereviewed using a Leica SP-2 confocal microscope, recorded and stored inJPEG format.

Results:

Peripheral blood cells showed considerable heterogeneity in theirstaining pattern with cells either negative, positive for a singleantibody only, or positive for both antibodies. This latter observationis demonstrated by the clear co-localisation of the fluorescent reportermolecules. Although the phenotype of positive cells is yet to beestablished DIC (differential interference contrast) imaging and Flowcytometry data indicate that positive cells are non-lymphocytic inorigin.

4. Animal Blood

4.1 Cats

A domestic cat (Cat 1) became unwell with weight loss, diarrhoea,distended abdomen and poor general condition. Ultrasound scan of theabdomen of the clinically affected animal showed thickening of the wallthroughout the colon. Endoscopy and biopsy by the veterinarian showedclinically and histologically that the animal had Inflammatory BowelDisease. Flow cytometry was performed on 2 EDTA blood samples over aperiod of 4 months. The proportion of total circulating white bloodcells infected with MAP in the cat was 7.6% and 9.8%. Immunofluorescencemicroscopy on the endoscopic biopsy samples from Cat 1 confirmed thepresence of MAP with a histological appearance similar to that seen inboth animals with Johne's disease and humans with Crohn's disease.

During this period, a new kitten (Cat 2) was introduced to the samehousehold. It was clinically well at the time of purchase from thebreeder. A week following introduction to the household, the kittendeveloped bloody diarrhoea. Routine stool microbiology was negative.Flow cytometry was again performed on 2 EDTA blood samples over a periodof 4 months. The proportion of circulating white cells infected with MAPwas 16.4% and 14.3%. These data confirmed that both animals had asystemic MAP infection.

4.2 Dairy Cows

EDTA blood samples were obtained from 4 dairy cows. These animals werepart of a closed dairy herd of more than 20 years standing with no knownclinical cases of Johne's disease. Intermittent ELISA testing ofindividual milk samples from the herd had shown that one of the 4sampled cows had had 2 positive ELISA readings and 2 other sampled cowshad had 1 positive ELISA reading amongst multiple negative results. Thefourth cow had had no raised ELISA readings on milk at all. Flowcytometry was performed on the 4 blood samples using A0X/A0XP andA4/XA4P pairs of monoclonal antibodies. The results showed that theproportions of the total circulating white blood cell populations inthese animals infected with intracellular MAP, were 10.9%, 36.3%, 40.1%,and 45.2%. These results are a further indication of the ability of asignificant systemic MAP infection to persist in a subclinical state.They also demonstrate that the present diagnostic technology has a muchgreater sensitivity than conventional diagnostic methods with theability to reveal the true scale of the long term threat to animal andhuman health posed by these pathogens.

5. Human Breast Milk

A 3 month old male child presented with rectal bleeding and episodes ofabdominal pain. He was investigated including upper and lowerGastrointestinal endoscopy with multiple biopsies, which led to theestablishment of a diagnosis of Crohn's disease at 8 months. MAP tests,subsequently requested and carried out on his paraffin embeddedhistopathology blocks showed extensive infection with MAP of the stomachand duodenum and in all biopsies from the terminal ileum to the rectum.His mother, who did not have Crohn's disease, had never fed him anythingexcept her own milk. However she had been diagnosed with auto-immunethyroiditis which is linked genetically to Crohn's disease. MAP testingrequested by her on a 50 ml sample of expressed breast milk showedabundant MAP infected cells in the centrifugal pellet.

6. Human Skin Samples in Psoriasis

3-4 mm punch biopsy full thickness skin samples were obtained underlocal anaesthesia from 2 adults each diagnosed with Psoriasis. Sampleswere taken from the central region of a psoriatic skin lesion and anadditional sample from the periphery of the lesion overlapping withnormal skin. A normal skin sample between lesions was also obtained.Samples were formalin fixed, processed and embedded in routinehistopathology blocks, following standard procedures. Sections of 2 μmwere cut, immobilised on Vectabond microscope slides, treated forantigen retrieval, and stained with XA1/A4 monoclonal antibodies andexamined by confocal microscopy.

Biopsies taken from within the psoriatic lesions were positive for MAPin both adults. Gold colocalisation of XA1 and A4 was seen ininflammatory cells in the thickened epidermal layer with stainingpersisting into the stratum corneum. Staining was also conspicuous inthe germinal layer. Positive MAP staining extended throughoutinflammatory cells in the rete and in inflammatory cells within thedermis. MAP positive cells were also seen around the hair follicles. Aconspicuous associated feature was the presence of MAP within thepilo-sebaceous unit.

An abnormality of sebaceous glands might contribute to the dry, scalynature of the superficial layers of psoriatic plaques. A furtherconspicuous feature in the dermis was MAP involvement of neurovascularbundles with colocalising XA1/A4 staining of these pathogens withinthickened arterial walls and perivascular connective tissues. MAPstaining of adjacent nerve bundles was also seen. Staining from biopsiestaken at the periphery of psoriatic plaques showed that MAP stainingstopped at the boundary between the plaque and normal skin. MAP was alsoabsent from biopsies of normal looking skin between plaques. This wouldbe consistent with a role for MAP in psoriatic plaque formation.

7. Measuring the Proportion of MAP Positive Cells in Synovial JointFluid in Arthritis

An adult female human with Psoriasis presented with discomfort and anacute effusion in her right knee joint. There was no history of trauma.The joint was warm and distended but was not acutely tender. Otherjoints were unaffected. A 20 ml sample of straw coloured slightlyopalescent fluid was aspirated and the cells separated bycentrifugation. These were washed, stained with fluorophore labelledA0X/A0XP and examined by flow cytometry. The proportion of cellscontaining MAP in the joint fluid was 8.56%. This was similar to the %of MAP-positive peripheral white blood cells in her blood at the time.

8. Food Safety Testing

8.1 MAP Tests for Contamination of Retail Milk

MAP infection of farm animals has become a global problem. Humanpopulations are widely exposed to MAP particularly in dairy products.New initiatives in the development of sufficiently sensitive diagnosticprocedures in the veterinary and food sector are available using massspectrometry, multiplex-bead based immunoassays and combined phage-PCRassay (Li et al. Early detection of Mycobacterium avium subsp.paratuberculosis infection in cattle with multiplex-bead basedimmunoassays. PLoS ONE 12(12): 2017 e0189783; Ricci M et al. ExploringMALDI-TOF MS approach for a rapid identification of Mycobacterium aviumssp. paratuberculosis field isolates Journal of Applied Microbiology122, 568-577 2016; Botsaris G et al. Detection of viable Mycobacteriumavium subspecies paratuberculosis in powdered infant formula byphage-PCR and confirmed by culture. International Journal of FoodMicrobiology Volume 216, 2016: 91-94).

There is an extensive literature on MAP diagnostic tests but in practisethey are rarely applied commercially. This is generally because MAP isnot widely recognised as a human pathogen and the available MAP testprocedures at present require customised DNA extraction and PCR. Newapproaches are being taken in the veterinary sector using massspectrometry and multiplex-bead based immunoassays.

The A0X, A0XP, XA1, A4 and XA4P anti-MAP antibodies can be used singlyand together accessing available read-out systems, such as, for example,Flow Cytometry and Mass Spectrometry, to provide quantitative economicsensitive and automatable detection systems.

8.2 MAP Tests for Contamination of Meat

MAP contamination of the surface of meat can occur in abattoirs. Whereasdestruction of these organisms would occur during normal cooking, thismight not be the case for ground beef where they would be dispersedthroughout the meat sample. Little is known at present of thedistribution of MAP in bovine skeletal muscle because of the lack of asensitive specific method for detecting MAP microscopically. The presentdiagnostic technology was applied to meat samples obtained from 10 cows,each of which was suspected of being MAP infected. Samples of skeletalmuscle from each of the animals was tested initially by laboratoryculture of MAP followed by PCR on the culture. Five of the cows hadproved positive and 5 negative. In the present diagnostic method sampleswere fixed in formalin, processed and paraffin embedded followingstandard histopathology procedures. 3 μm sections were taken from eachblock and processed by antigen retrieval followed by staining with pairsof antibodies comprising A1/A4 and A0X/A4 and A0X/A0XP. Positive sampleswere ranked 1 (low) to 5 (high) according to the severity anddistribution of MAP.

Nine of the 10 samples tested MAP positive, 2 at level 1, 3 at level 2,2 at level 3 and 1 each at levels 4 and 5. MAP positive cells were seento align along the sarcolemma of muscle fibres and withininterfibrillary spaces. From level 3 upwards MAP extended rightthroughout the substance of the sample with organisms and their peptideproducts within muscle fibres as well as between them. Clusters of freeMAP organisms invading muscle fibres were seen to disrupt theirstructure with some foci of apparent necrosis. The extent of MAPinvolvement throughout large areas of muscle was conspicuously greaterthan had previously been expected.

9. Testing Environmental Samples Such as Surface Waters, Rivers, WaterTreatment Plants, Domestic Water Systems, Aerosols and Samples of Soiland Sediments.

The technical difficulties which have affected MAP testing of clinicalsamples also apply to those used in testing MAP in samples from rivercatchments, between release from an infected animal into theenvironment, to human exposure. The A0X, A0XP, XA1, A4, and XA4Pantibodies and their corresponding MAP peptides in the present work maybe used to capture and measure MAP and MAP peptides.

Example 3: Specificity of Antibodies for MAP

1. Staining of Cultured MAP and Related Mycobacteria in theirExtracellular Phenotype.

Mycobacterial Culture.

Two strains of Mycobacterium avium subspecies paratuberculosis (MAP) K10and M47508 were grown on Herold's egg yolk agar slants with Mycobactin J(BD BBL prepared media). Purity was monitored by using Herrold's eggyolk agar slants without Mycobactin J (BD BBL). Non-Mycobacteriumstrains were grown on Middlebrooks 7H10 agar plates (BD BBL). Whengrowth was observed, individual colonies were suspended in 1 ml PBS andcentrifuged at 13,000 rpm for 1 minute in a micro centrifuge, thesupernatant removed and the pellet suspended in 1 ml PBS:

Mycobacterial Staining:

200 μl of cultured cells were aliquoted onto Vectabond (VectorLaboratories, Peterborough UK) coated slides and when air dried andfixed with 10% formalin (BDH) for 30 mins. Slides were washed threetimes in 1×PBS (PH 7.4) and incubated at 37° overnight to ensureadhesion. Permeabilisation of the mycobacterial envelope was achieved byincubation in lysozyme (2 mg ml, prepared in water) followed by 5 min atroom temperature with 0.1% triton X-100. Non-specific Fc receptorbinding was blocked by incubating the slides with TrueStain FcX(Cambridge BioScience, Cambridge UK) @ 1/50 for 30 mins followed by abrief wash in 1×PBS. In order to establish antibody specificity aduplicate set of slides were stained in which the individual monoclonalantibodies had been incubated with their corresponding peptides for 1 hrat a concentration of 0.5 mg/ml prior to incubation. Slides were thenincubated in primary antibody at the following dilutions: A0X ( 1/1500),A0XP ( 1/2500), A4 ( 1/1500), XA4P ( 1/2500) overnight at 4° C. on anorbital shaker. Sections were washed three times in 1×PBS each for 5mins and incubated in secondary antibody conjugated with Dylite 550(Thermo Fisher Scientific UK) @ 1/1500 for 45 mins at RT. Sections werewashed three times in 1×PBS each for 5 mins before mounting in Aqueousmountant (Sigma F4680).

Results:

A0X, A0XP, A4 and XA4P monoclonal antibodies showed positive stainingfor both MAP cultures K10 and M47508 but were negative for all closelyrelated strains tested (see Table 3). Staining of MAP cultures wasabsent when blocked with corresponding peptides but present whenantibodies were incubated with non-corresponding peptides. These dataindicate unique specificity of these four monoclonal antibodies forlaboratory cultured MAP and not for the selected closely relatedspecies.

TABLE 3 Blocking Blocking Blocking Blocking Mycobacterial PeptidePeptide Peptide Peptide strain Antibody A0X A0XP A4 XA4P K10 A0X − + + +K10 A0XP + − + + K10 A4 + + − + K10 XA4P + + + − M47508 A0X − + + +M47508 A0XP + − + + M47508 A4 + + − + M47508 XA4P + + + − M avium sspavium A0X − − − − M avium ssp avium A0XP − − − − M avium ssp avium A4 −− − − M avium ssp avium XA4P − − − − M avium ssp sylvat A0X − − − − Mavium ssp sylvat A0XP − − − − M avium ssp sylvat A4 − − − − M avium sspsylvat XA4P − − − − M avium 2333 A0X − − − − M avium 2333 A0XP − − − − Mavium 2333 A4 − − − − M avium 2333 XA4P − − − − M avium chelonae A0X − −− − M avium chelonae A0XP − − − − M avium chelonae A4 − − − − M aviumchelonae XA4P − − − − M porcinum A0X − − − − M porcinum A0XP − − − − Mporcinum A4 − − − − M porcinum XA4P − − − − M Rhodesiae A0X − − − − MRhodesiae A0XP − − − − M Rhodesiae A4 − − − − M Rhodesiae XA4P − − − − Mthermoresistibile A0X − − − − M thermoresistibile A0XP − − − − Mthermoresistibile A4 − − − − M thermoresistibile XA4P − − − −2. Staining of MAP and Related Mycobacteria in their IntracellularPhenotype in U937 Cell Culture.

Cell Culture:

U937 a human pro-monocytic cell line was grown in RPMI 1640 plus 10%foetal calf serum (FCS) and 100 U/ml penicillin and 100 μl/mlstreptomycin at 37° C. in a humidified atmosphere with 5% CO₂.

Infection:

When the U937 cells were in exponential growth phase they were counted,and viability assessed. 2×10⁵ cells/ml at 95% viability were cultured in2 mls RPMI 1640 plus 10% foetal calf serum (FCS) without antibiotics andchallenged with Mycobacterium paratuberculosis K10 at an infection ratioof approximately 10:1. The cells were then incubated at 37° C. in ahumidified atmosphere with 5% CO² for 5 hours, then re-suspended in 2mls of fresh growth media and cultured for a further 48 hours.

Staining:

Four separate aliquots of cells containing 2×10⁵ cells/ml were taken andcentrifuged at 1200 rpm for 5 mins. Cells were washed by re-suspensionin 5 mls of PBS and centrifuged at 1200 for 5 mins. This was repeatedthree times. Monoclonal antibodies A0X, A0XP, A4 and XA4P wereconjugated with either Fluorescein (Innova Biosciences kit 707-0015) orPE-Cy 5.5 (kit 761-0015) and then added to the cells so that the finalconcentrations of antibodies were 1/1500, 1/2500, 1/1500, 1/2500respectively. Cells were left to incubate at room temperature for 1 hr,washed three times by the addition of ×3 volume of 1×PBS (PH 7.4) andcentrifugation at 1500 rpm. 2000 of stained cells were aliquoted onto aVectabond (Cole-Partner, St. Neots, UK) microscope slide and viewedusing a Leica SP2 confocal microscope.

Results:

Immunofluorescence microscopy using the four directly conjugatedmonoclonal antibodies A0X, A0XP, A4 and XA4P identified positiveIntracellular localisation of the MAP strain K10 within thepro-monocytic cell line U937. Localisation was confirmed using DIC(differential interference contrast) imaging.

3. ELISAs of A0X, A0XP, A4 and XA4P Monoclonal Anti-MAP AntibodiesBinding to the Same Peptides and Related Peptides in Other Organisms.

Arrangements were made with the Suppliers of the 4 principal anti-MAPmonoclonal antibodies to carry out ELISAs on the final protein Aaffinity purified monoclonal reagents. Of great importance was the needto use Streptavidin coated ELISA plates to immobilise the synthetictarget peptides in the wells via Biotin linkage. Coating the wells withsynthetic peptide only was unsuitable for the antibodies to syntheticpeptide immunogens in the present work.

A0X Clone 18C2/1C2 Mouse IgG1

Immunogen: BSA-MVINDDAQRLLSQR-amide (SEQ ID NO: 93) IgG IgM 1:10,0001:50,000 1:100,000 1:10,000 1:50,000 1:100,000 Bio-MVINDDAQRLLSQR-amide1.254 0.598 0.302 0.068 0.075 0.073 (SEQ ID NO: 75)Bio-MSINDDAQKLKDRL-amide 0.064 0.057 0.057 0.063 0.066 0.077(SEQ ID NO: 76) Bio-MVINDDAQRLL[pS]QR- 0.061 0.056 0.057 0.063 0.0650.069 amide (SEQ ID NO: 77)

A0XP Clone 3D2/2C5 Mouse IgG1

Immunogen: BSA-MVINDDAQRLL(pS)QR (SEQ ID NO: 94) IgG IgM 1:1000 1:1000Bio-MVINDDAQRLL[pS]QR-amide 0.741 0.173 (SEQ ID NO: 79)Bio-MVINDDAQRLLSQR-amide 0.185 0.186 (SEQ ID NO: 80)

A4 Clone 3F7A7/A12 Mouse IgG2a

Immunogen: BSA-VSIRTDPSSR-amide (SEQ ID NO: 95) IgG IgM 1:2000 1:50001:10,000 1:2000 1:5000 1:10,000 Bio-VSIRTDPSSR-amide 0.577 0.386 0.1940.068 0.064 0.074 (SEQ ID NO: 64) Bio-SIRSDPSSR-amide 0.082 0.068 0.0640.069 0.064 0.081 (SEQ ID NO: 66) Bio-YSIRSDPASR-amide 0.088 0.07 0.0620.068 0.067 0.072 (SEQ ID NO: 67) Bio-VSVRYDPSSR-amide 0.082 0.076 0.070.069 0.085 0.078 (SEQ ID NO: 68) Bio-IAIRTDPASR-amide 0.11 0.079 0.0730.081 0.076 0.094 (SEQ ID NO: 69)

XA4P Clone 2D4/1B5 Mouse IgG2a

Immunogen: BSA-YLSALVSIRTDPS(pS)R-amide (SEQ ID NO: 96) IgG IgM 1:20001:2000 Bio-YLSALVSIRTDPS[pS]R-amide 1.329 0.146 (SEQ ID NO: 88)Bio-YLSALVSIRTDPSSR-amide 0.066 0.062 (SEQ ID NO: 89)Bio-YLSALYSIRSDPA[pS]R-amide 0.286 0.072 (SEQ ID NO: 90)Bio-YLSALVSVRYDPS[pS]R 1.374 0.134 (SEQ ID NO: 91)Bio-YLSAQIAIRTDPA[pS]R-amide 0.380 0.073 (SEQ ID NO: 92)

4. Differential Blockade of Antibody Staining of Tissues by theIdentical Synthetic Target Peptide and not by Unrelated Peptides.

2 μm paraffin tissue sections were taken from the caecum and ascendingcolon of a Crohn's patient and individually stained with the fourmonoclonal antibodies A0X, A0XP, A4 and XA4P. In order to establishantibody specificity and exclude non-specific staining a parallel set oftissue sections were stained with the four monoclonal antibodiespre-incubated with 0.5 μg of synthetic peptide corresponding to theindividual antigenic sequences.

Results:

A0X staining identified clusters of MAP positive cells within the laminapropria and occasional cells within blood vessels. Signal was blocked tonear completion by pre-incubation with A0X peptide. No apparent stainingin of the human gut tissue in either blocked or un-blocked sections wasobserved when stained with A0XP. Staining with A4 showed occasionalpositive cells within the lamina propria which was partially blockedwith prior incubation with A4 peptide. XA4P staining identified bothintra and perivascular staining of MAP positive cells in addition tofoci of positive cells within the lamina propria. Blockade withpre-incubation of XA4P peptide partially blocked this staining.

1. A method of diagnosing or monitoring Mycobacterium avium subspeciesparatuberculosis (MAP) infection, which method comprises detecting thepresence of the polypeptide (MAP P900) encoded by the positive strand ofIS900, or a fragment thereof, in a sample from a subject, wherein MAPP900, or a fragment thereof, is detected using an antibody, or anantigen-binding fragment thereof, that binds to MAP P900.
 2. A methodaccording to claim 1, wherein the antibody, or an antigen-bindingfragment thereof, binds the region of MAP P900 defined by amino acids 24to 71 or 329 to 386 of SEQ ID NO:
 1. 3. A method according to claim 1,wherein the antibody, or an antigen-binding fragment thereof, binds theregion of MAP P900 defined by: amino acids 26 to 71 of SEQ ID NO: 1;amino acids or 329 to 385 of SEQ ID NO: 1; amino acids 26 to 39 of SEQID NO: 1; amino acids or 52 to 68 of SEQ ID NO: 1; amino acids or 345 to359 or 350 to 359 of SEQ ID NO: 1; amino acids 26 to 71 of SEQ ID NO: 1,wherein serine 37 is phosphorylated; amino acids or 345 to 359 or 350 to359 of SEQ ID NO: 1, wherein serine 357 is phosphorylated and/or serine358 is phosphorylated.
 4. A method according to claim 1, wherein two ormore of said antibodies, or antigen-binding fragments thereof, are usedto detect MAP P900.
 5. A method according to claim 4, wherein the methoduses: at least one antibody that binds to the region of MAP P900 definedby amino acids 26 to 71 of SEQ ID NO: 1 and at least one furtherantibody that binds to the region of MAP P900 defined by amino acids or329 to 385 of SEQ ID NO: 1; at least one antibody that binds to theregion of MAP P900 defined by amino acids 26 to 39 of SEQ ID NO: 1 andat least one further antibody that binds to the region of MAP P900defined by amino acids or 52 to 68 of SEQ ID NO: 1; at least oneantibody that binds to the region of MAP P900 defined by amino acids 52to 68 of SEQ ID NO: 1 and at least one further antibody that binds tothe region of MAP P900 defined by amino acids or 345 to 359 or 350 to359 of SEQ ID NO: 1; at least one antibody that binds to the region ofMAP P900 defined by amino acids 26 to 71 of SEQ ID NO: 1, wherein serine37 is optionally phosphorylated and at least one further antibody thatbinds to the region of MAP P900 defined by amino acids or 345 to 359 or350 to 359 of SEQ ID NO: 1, wherein serine 357 and/or serine 358 isoptionally phosphorylated.
 6. A method according to claim 5, wherein themethod comprises determining whether the region of MAP P900 betweenamino acids 273 to 406 of SEQ ID NO: 1, or a fragment of either thereof,has been cleaved from membrane-bound MAP P900.
 7. A method according toclaim 6, wherein the method comprises determining whether the cleavedregion of MAP P900, or fragment thereof, has spread from microbial cellsand/or host cells containing membrane bound MAP P900.
 8. A methodaccording to claim 2, wherein the antibody that binds to the region ofMAP P900 defined by amino acids 24 to 71 binds to the amino acidsequence MVINDDAQRLLSQR, AAVTTLADGGEVTWAID or MVINDDAQRLL[pS]QR and/orthe antibody that binds to the region of MAP P900 defined by amino acids329 to 386 of SEQ ID NO: 1 binds to the amino acid sequenceYLSALVSIRTDPSSR or NLKRPRRYDRRLLRA or to the amino acid sequenceYLSALVSIRTDPSSR in which one of more of the serine residues isphosphorylated.
 9. A method according to claim 4, wherein the methoduses at least one antibody that specifically binds to anon-phosphorylated MAP P900 sequence and at least one further antibodythat specifically binds to phosphorylated MAP P900 sequence.
 10. Amethod according to claim 9, wherein the non-phosphorylated MAP P900sequence is MVINDDAQRLLSQR, and the phosphorylated MAP P900 sequence isMVINDDAQRLL[pS]QR, or the non-phosphorylated MAP P900 sequence isYLSALVSIRTDPSSR or VSIRTDPSSR, and the phosphorylated MAP P900 sequenceis YLSALVSIRTDPS[pS]R, YLSALVSIRTDP[pS]SR, VSIRTDP[pS][pS]R,VSIRTDP[pS]SR or VSIRTDP[pS][pS]R.
 11. A method according to claim 1,wherein the sample is a sample of a body fluid or a tissue sample.
 12. Amethod according to claim 11, wherein body fluid is blood, semen,amniotic fluid, cerebrospinal fluid, synovial fluid or breast milk, orthe tissue is skin sample, gastrointestinal tract, thyroid, lymph node,brain or genitourinary tract.
 13. A method according to claim 1, whereinthe subject has Crohn's disease, psoriasis, thyroiditis, Parkinson'sdisease, type 1 diabetes, arthritis, ankylosing spondylitis, irritablebowel syndrome, ulcerative colitis, inflammatory bowel disease,Alzheimer's disease, multiple sclerosis, sarcoidosis, idiopathicpulmonary fibrosis and/or chronic fatigue syndrome.
 14. A methodaccording to claim 1, wherein the subject is an animal.
 15. An antibody,or antigen-binding fragment thereof, which specifically binds to theregion of MAP P900 defined by amino acids 26 to 71 of SEQ ID NO: 1, to aphosphorylated sequence within the region of MAP P900 defined by aminoacids 26 to 71 or 345 to 371 of SEQ ID NO: 1, or to the amino acidsequence YLSALVSIRTDPSSR or NLKRPRRYDRRLLRA or a phosphorylated form ofeither thereof, within the region of MAP P900 defined by amino acids 329to 360 of SEQ ID NO:
 1. 16. An antibody, or antigen-binding fragmentthereof, according to claim 15, wherein the antibody binds to the aminoacid sequence MVINDDAQRLLSQR, AAVTTLADGGEVTWAID or MVINDDAQRLL[pS]QR.17. (canceled)
 18. An antibody, or antigen-binding fragment thereof,according to claim 15, wherein the antibody binds to the sequenceMVINDDAQRLLSQR or YLSALVSIRTDPSSR, when one or more of the serineresidues is phosphorylated.
 19. (canceled)
 20. An antibody according toclaim 15 which is a monoclonal, chimeric, recombinant, synthetic orsingle domain antibody.
 21. An antibody according to claim 15 which is alabelled antibody.
 22. (canceled)
 23. (canceled)
 24. A method ofdetecting MAP in a food product or an environment sample, or ofcapturing a peptide for Mass Spectrometry (MS) characterisation, themethod comprising contacting the food product, or a sample thereof, theenvironmental sample, or the peptide with an antibody, orantigen-binding fragment thereof, as defined in claim
 15. 25. A methodaccording to claim 24 wherein the food product is milk or other dairyproduct or a meat product.
 26. (canceled)
 27. A method according toclaim 24 wherein the environmental sample is a sample of surface water,river water, water-treatment plant water, domestic water, or an aerosol,soil or sediment.
 28. (canceled)
 29. A peptide fragment of MAP P900 ofup to 40 amino acids comprising one or more of the following sequences:MVINDDAQRLLSQR, VTTLADGGEVTWAID, NLKRPRRYDRRLLRA, VSIRTDPSSR andYLSALVSIRTDPSSR, wherein the peptide is optionally phosphorylated.
 30. Apeptide according to claim 29, wherein the peptide consists of up to 25amino acids of the MAP P900 amino acid sequence.
 31. A peptide accordingto claim 29, wherein the peptide is phosphorylated and comprises one ofthe following sequences: MVINDDAQRLL[pS]QR or YLSALVSIRTDPS[pS]R,YLSALVSIRTDP[pS]SR or YLSALVSIRTDP[pS][pS]R.
 32. A peptide according toclaim 29, wherein the peptide is modified at the N-terminus and/or atthe C-terminus and/or is conjugated or coupled to a carrier molecule.33. A method of generating an antibody that specifically binds to MAPP900, which method comprises administering a peptide according to claim29 to a laboratory animal to generate an immune response and isolatingantibodies from the animal.
 34. A method according to claim 33, whichfurther comprises screening the isolated antibodies for specific bindingto MAP P900 by determining whether the antibodies bind to the saidpeptide and whether the antibodies bind to homologous peptides fromrelated organisms, wherein a peptide is specific for MAP P900 when itbinds to the said peptide but does not bind to the homologous peptidesfrom related organisms.
 35. (canceled)
 36. A method of treating orpreventing MAP infection, the method comprising administering anantibody, or antigen-binding fragment thereof, as defined in claim 15 toa subject in need thereof.